Metal borides and uses thereof

ABSTRACT

Disclosed herein are compounds, methods, and tools which comprise tungsten borides and mixed transition metal borides.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.62/583,316, filed Nov. 8, 2017, which application is incorporated hereinby reference.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention was made with Government support under Grant Numbers0654431 and 1506860, awarded by the National Science Foundation. TheGovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

In many manufacturing processes, materials must be cut, formed, ordrilled and their surfaces protected with wear-resistant coatings.Diamond has traditionally been the material of choice for theseapplications, due to its superior mechanical properties, e.g.hardness >70 GPa. However, diamond is rare in nature and difficult tosynthesize artificially due to the need for a combination of hightemperature and high pressure conditions. Industrial applications ofdiamond are thus generally limited by cost. Moreover, diamond is not agood option for high-speed cutting of ferrous alloys due to itsgraphitization on the material's surface and formation of brittlecarbides, which leads to poor cutting performance. Metal borides may bean attractive alternative to diamond due to their desirable propertiesand greater synthetic accessibility.

SUMMARY OF THE INVENTION

Described herein is a method of preparing a composite matrix comprising:

combining a sufficient amount of W with an amount of B and optionally Mto generate the composite matrix, wherein the ratio of B to W and M isless than 12 equivalents of B to 1 equivalent of W and M; and

the composite matrix comprises:W_(1-x)M_(x)B₄

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al); and

x is from 0 to 0.999.

Disclosed herein is a method of producing a thermodynamically stabletungsten tetraboride composite matrix, the method comprising:

-   -   a) adding into a compression chamber a mixture of boron (B) and        tungsten (W), wherein the ratio of boron to tungsten is between        4 and 11.9 equivalents of boron to 1 equivalent of tungsten;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the thermodynamically        stable WB₄ composite matrix.

Disclosed herein is a tool comprising a composite matrix produced by themethods described herein.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention are set forth with particularity in theappended claims. A better understanding of the features and advantagesof the present invention will be obtained by reference to the followingdetailed description that sets forth illustrative embodiments, in whichthe principles of the invention are utilized, and the accompanyingdrawings of which:

FIG. 1 shows the crystal structure of WB₄ as determined by X-raydiffraction techniques.

FIG. 2 shows X-ray powder diffractograms of WB_(x) with variable boroncontent.

FIG. 3 shows X-ray powder diffractograms of W_(1-x)Ta_(x)B₄.

FIG. 4 shows X-ray powder diffractograms of W_(1-x)Nb_(x)B₄.

FIG. 5 shows X-ray powder diffractograms of W_(1-x)V_(x)B₄.

FIG. 6 shows X-ray powder diffractograms of W_(1-x)Mo_(x)B₄.

FIG. 7 shows X-ray powder diffractograms of W_(1-x)Re_(x)B₄.

FIG. 8 shows X-ray powder diffractograms of W_(1-x)Cr_(x)B₄.

FIG. 9 shows the thermal stability of WB₄ prepared with a W:B ratio of1:11.6 and 1:9.0 as measure by thermal gravimetric analysis in air.

FIG. 10 shows SEM images of selected samples of WB_(x) prepared with a Wto B ratio from 1:11.6 to 1:4.5.

FIG. 11 shows SEM images and elemental maps of selected samples ofWB_(x) prepared with a W to B ratio 1:4.5.

FIG. 12 shows SEM images and elemental maps of the W_(0.668)Ta_(0.332)B₄alloy.

DETAILED DESCRIPTION OF THE INVENTION

Tungsten tetraboride is useful as a superhard coating for tools used tocut or abrade. In some instances, tungsten tetraboride is prepared withtungsten and boron at a ratio of 1 equivalent of tungsten to 12equivalents of boron. In such cases, the high ratio of boron to tungsteneliminates the formation of metal side products such as tungstenmonoboride and tungsten diboride, which cannot be separated from thetungsten tetraboride composite. The presence of metal side productsnegatively affects the mechanical properties of the composite.Furthermore, the excess boron can also be detrimental and expensive inthe context of an industrial setting.

Described herein is a method of preparing a composite matrix comprising:

combining a sufficient amount of W with an amount of B and optionally Mto generate the composite matrix, wherein the ratio of B to W and M isless than 12 equivalents of B to 1 equivalent of W and M; and

the composite matrix comprises:W_(1-x)M_(x)B₄

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al); and

x is from 0 to 0.999.

In some embodiments, the combining comprises i) mixing W, B, andoptionally M to generate a mixture, ii) transferring the mixture to areaction vessel, and iii) heating the mixture to a temperaturesufficient to induce a reaction between W, B, and optionally M togenerate the composite matrix.

In some embodiments, the reaction is a solid state reaction. In someembodiments, at least one reaction component is partially melted. Insome embodiments, at least one reaction component is completely melted.In some embodiments, the reaction vessel is further subjected under aninert atmosphere after transferring the mixture to the reaction vesselbut prior to heating the mixture. In some embodiments, oxygen is removedfrom the reaction vessel to generate the inert atmosphere.

In some embodiments, a vacuum is applied to the reaction vessel togenerate the inert atmosphere. In some embodiments, the vacuum isapplied for a time sufficient to remove at least 99% of oxygen from thereaction vessel. In some embodiments, the vacuum is applied for at least10 minutes, 20 minutes, 30 minutes, or more. In some embodiments, thereaction vessel is purged with an inert gas to generate the inertatmosphere. In some embodiments, the inert gas comprises argon,nitrogen, or helium. In some embodiments, the reaction vessel issubjected to at least one cycle of applying a vacuum and flushing thereaction vessel with an inert gas to remove oxygen from the reactionvessel.

In some embodiments, the mixture is heated to a temperature betweenabout 1200° C. and about 2200° C. In some embodiments, the mixture isheated to a temperature of about 1400° C., 1500° C., 1600° C., 1700° C.,1800° C., 2000° C., 2100° C., or about 2200° C. In some embodiments, themixture is heated for about 15 minutes, 90 minutes, 120 minutes, 180minutes, 240 minutes, 360 minutes, or more. In some embodiments, themixture is heated by an electric arc furnace. In some embodiments, areaction vessel of the electric arc furnace is subjected to an inertatmosphere after transferring the mixture to the reaction vessel butprior to heating the mixture. In some embodiments, the inert atmosphereis generated by either applying a vacuum to the reaction vessel,flushing the reaction vessel with an inert gas or any combinationsthereof. In some embodiments, the reaction vessel is optionally coatedwith an electrically insulating material. In some embodiments, at mostabout 95%, 90%, 85%, 80%, 70%, 60%, 50%, 40%, 30%, or less of thesurface of the reaction vessel is optionally coated with theelectrically insulating material. In some embodiments, the insulatingmaterial comprises hexagonal boron nitride (h-BN). In some embodiments,the mixture is heated until a liquid solution is formed.

In some embodiments, the mixture is heated by an induction furnace. Insome embodiments, the induction furnace is heated by electromagneticinduction. In some embodiments, the electromagnetic radiation used forelectromagnetic induction has the frequency and wavelength of radiowaves. In some embodiments, the mixture is heated by hot pressing. Insome embodiments, the mixture is heated by plasma spark sintering. Insome embodiments, a reaction vessel is subjected to an inert atmosphereafter transferring the mixture to the reaction vessel but prior toheating the mixture. In some embodiments, the inert atmosphere isgenerated by removing oxygen from the reaction vessel in combinationwith either applying a vacuum to the reaction vessel or flushing thereaction vessel with an inert gas. In some embodiments, the inert gas ishigh purity argon.

In some embodiments, M is at least one element selected from the group:vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum(Ta), and rhenium (Re). In some embodiments, x is from 0.001 to 0.999.In some embodiments, x is 0.201-0.400. In some embodiments, x is0.401-0.600. In some embodiments, x is 0.601-0.800. In some embodiments,x is 0.801-0.999. In some embodiments, the ratio of B to W and M is lessthan 5 equivalents of B to 1 equivalent of W and M. In some embodiments,the composite matrix comprises W1-xVxB4. In some embodiments, thecomposite matrix comprises W_(1-x)Cr_(x)B₄. In some embodiments, thecomposite matrix comprises W_(1-x)Nb_(x)B₄. In some embodiments, thecomposite matrix comprises W_(1-x)Mo_(x)B₄. In some embodiments, thecomposite matrix comprises W_(1-x)Ta_(x)B₄. In some embodiments, thecomposite matrix comprises W_(1-x)R_(e)xB₄.

In some embodiments, x is 0. In some embodiments, the ratio of B to W isbetween about 11.9 and about 9 equivalents of B to 1 equivalent of W. Insome embodiments, the ratio of B to W is about 11.6, about 11, about10.5, about 10, about 9.5, or about 9 equivalents of B to 1 equivalentof W. In some embodiments, the composite matrix comprises WB₄. In someembodiments, the composite matrix is formed with a W to B ratio of1:11.6. In some embodiments, the composite matrix has oxidationresistance below 450° C. In some embodiments, the composite matrix isformed with a W to B ratio of 1:10.5. In some embodiments, the compositematrix is formed with a W to B ratio of 1:9.0. In some embodiments, thecomposite matrix has oxidation resistance below 465° C.

In some embodiments, the composite matrix has a density at or above 4.0g/cm3. In some embodiments, the method further generates a metal sideproduct. In some embodiments, the metal side product is tungstendiboride or tungsten monoboride. In some embodiments, the metal sideproduct is less than 10%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or0.01% relative to the percentage of the composite matrix.

Disclosed herein is a method of producing a thermodynamically stabletungsten tetraboride composite matrix, the method comprising:

-   -   a) adding into a compression chamber a mixture of boron (B) and        tungsten (W), wherein the ratio of boron to tungsten is between        4 and 11.9 equivalents of boron to 1 equivalent of tungsten;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the thermodynamically        stable WB₄ composite matrix.

In some embodiments, the compressed raw mixture is heated by an electricarc furnace. In some embodiments, the arc furnace electrode comprisesgraphite or tungsten metal. In some embodiments, the reaction vessel isoptionally coated with an electrically insulating material. In someembodiments, at most about 95%, 90%, 85%, 80%, 70%, 60%, 50%, 40%, 30%,or less of the surface of the reaction vessel is optionally coated withthe electrically insulating material. In some embodiments, theinsulating material comprises hexagonal boron nitride (h-BN). In someembodiments, the insulating material does not contain carbon. In someembodiments, the compressed raw mixture is shielded from the arc furnaceelectrode by the electrically insulating material, optionally comprisinghexagonal boron nitride.

In some embodiments, the composite matrix is composed of grains orcrystallites that are less than 1000 micrometer in size. In someembodiments, the composite matrix is composed of grains or crystallitesthat are less than 100 micrometer in size. In some embodiments, thecomposite matrix is composed of grains or crystallites that are lessthan 50 micrometer in size. In some embodiments, the composite matrix iscomposed of grains or crystallites that are less than 10 micrometer insize. In some embodiments, the composite matrix is composed of grains orcrystallites that are less than 1 micrometer in size.

In some embodiments, the compressed raw mixture is heated by aninduction furnace. In some embodiments, the induction furnace is heatedby electromagnetic induction. In some embodiments, the electromagneticradiation used for electromagnetic induction has the frequency of radiowaves. In some embodiments, the mixture is heated by hot pressing. Insome embodiments, the mixture is heated by plasma spark sintering. Insome embodiments, the reaction vessel is water cooled. In someembodiments, the reaction vessel is graphite lined. In some embodiments,graphite is heated within the reaction vessel. In some embodiments, thecompressed raw mixture is shielded from the graphite lined reactionvessel by an electrically insulating material, optionally comprisinghexagonal boron nitride.

In some embodiments, the composite matrix is composed of crystallitesthat are less than 500 micrometers in size. In some embodiments, thecomposite matrix is composed of crystallites that are less than 200micrometers in size. In some embodiments, the composite matrix iscomposed of crystallites that are less than 50 micrometers in size.

In some embodiments, the density of the composite matrix is betweenabout 5.0 g/cm3 and about 7.0 g/cm3. In some embodiments, the density ofthe composite matrix is between about 5.1 g/cm3 and about 6.2 g/cm3.

In some embodiments, the composite matrix is formed with a W to B ratioof 1:11.6. In some embodiments, the composite matrix has oxidationresistance below 450° C. In some embodiments, the composite matrix isformed with a W to B ratio of 1:10.5. In some embodiments, the compositematrix is formed with a W to B ratio of 1:9.0. In some embodiments, thecomposite matrix has oxidation resistance below 465° C. In someembodiments, the composite matrix has a density at or above 4.0 g/cm³.

Described herein is a method of producing a composite matrix of Formula(II):W_(1-x)M_(x)B₄  (II)

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is from 0.001 to 0.999; and    -   wherein the method comprises:    -   a) adding into a compression chamber a mixture of boron,        tungsten, and M, wherein the ratio of boron to tungsten and M is        between 3.5 and 5.0 equivalents of boron to 1 equivalent of        tungsten and M;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the composite matrix of        Formula (II).

In some embodiments, the compressed raw mixture is heated by an electricarc furnace. In some embodiments, the arc furnace electrode is made ofgraphite or tungsten metal. In some embodiments, the compressed rawmixture is partially shielded from the arc furnace electrode by anelectrically insulating material, optionally comprising hexagonal boronnitride.

In some embodiments, the composite matrix is composed of grains orcrystallites that are less than 100 micrometer in size. In someembodiments, the composite matrix is composed of grains or crystallitesthat are less than 50 micrometer in size. In some embodiments, thecomposite matrix is composed of grains or crystallites that are lessthan 10 micrometer in size. In some embodiments, the composite matrix iscomposed of crystallites that are less than 1 micrometer in size.

In some embodiments, the compressed raw mixture is heated by aninduction furnace. In some embodiments, the induction furnace is heatedby electromagnetic induction. In some embodiments, the electromagneticradiation used for electromagnetic induction has the frequency of radiowaves. In some embodiments, the mixture is heated by hot pressing. Insome embodiments, the mixture is heated by plasma spark sintering. Insome embodiments, the reaction vessel is water cooled. In someembodiments, the reaction vessel is graphite lined. In some embodiments,the radiofrequency induction is tuned to carbon, and the graphite isheated within the reaction vessel. In some embodiments, the compressedraw mixture is shielded from the graphite lined reaction vessel by anelectrically insulating material, optionally comprising hexagonal boronnitride.

In some embodiments, the composite matrix is composed of grains orcrystallites that are less than 100 micrometer in size. In someembodiments, the composite matrix is composed of grains or crystallitesthat are less than 50 micrometer in size. In some embodiments, thecomposite matrix is composed of grains or crystallites that are lessthan 10 micrometer in size.

In some embodiments, x is 0.001-0.200. In some embodiments, x is0.201-0.400. In some embodiments, x is 0.401-0.600. In some embodiments,x is 0.601-0.800. In some embodiments, x is 0.801-0.999.

In some embodiments, M is at least one element selected from the group:vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum(Ta), and rhenium (Re). In some embodiments, composite matrix comprisesW_(1-x)V_(x)B₄. In some embodiments, the composite matrix comprisesW_(1-x)Cr_(x)B₄. In some embodiments, the composite matrix comprisesW_(1-x)Nb_(x)B₄. In some embodiments, the composite matrix comprisesW_(1-x)Mo_(x)B₄. In some embodiments, the composite matrix comprisesW_(1-x)Ta_(x)B₄. In some embodiments, the composite matrix comprisesW_(1-x)Re_(x)B₄.

Disclosed herein is a method of producing a composite materialcomprising a composite matrix of Formula (III):W_(1-x)M_(x)B₄  (III)

-   -   wherein the percentage of the composite matrix of Formula (III)        and boron relative to the composite material is at least 95%,        wherein,    -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is from 0 to 0.999; and    -   wherein the method comprises:    -   a) adding into a compression chamber a mixture of boron,        tungsten, and optionally M, wherein the ratio of boron to        tungsten and optionally M is less than 12.0 equivalents of boron        to 1 equivalent of tungsten and optionally M;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) partially lining the interior of the reaction vessel with an        electric insulator to generate an insulated reaction vessel;    -   d) adding the compressed raw mixture to the insulated reaction        vessel;    -   e) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the insulated reaction vessel, flushing the        insulated reaction vessel with inert gas, or a combination        thereof;    -   f) arc melting the compressed raw mixture until at least 95% or        more of the compressed raw mixture is melted; and    -   g) cooling the insulated reaction vessel, thereby generating the        composite material comprising the composite matrix of Formula        (III).

In some embodiments, the composite material further comprises a metalside product, wherein optionally said metal side product is less than4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% relative to the percentageof the composite matrix. In some embodiments, the metal side product istungsten diboride or tungsten monoboride. In some embodiments, at mostabout 95%, 90%, 85%, 80%, 70%, 60%, 50%, 40%, 30%, or less of thesurface of the reaction vessel is coated with the electricallyinsulating material. In some embodiments, the compressed raw mixture ispartially shielded from the arc furnace electrode by an electricallyinsulating material, optionally comprising hexagonal boron nitride. Insome embodiments, the insulating material comprises hexagonal boronnitride (h-BN).

In some embodiments, the compressed raw mixture is melted by an electricarc furnace or plasma arc furnace. In some embodiments, the arc furnaceelectrode is made of graphite or tungsten metal. In some embodiments, inreaction vessel is water cooled. In some embodiments, the cooling rateof the reaction vessel is controlled. In some embodiments, the reactionvessel is allowed to cool to ambient temperature.

In some embodiments, the composite matrix is composed of grains orcrystallites that are less than 100 micrometer in size. In someembodiments, the composite matrix is composed of grains or crystallitesthat are less than 123-133 micrometer in size. In some embodiments, thecomposite matrix is composed of grains or crystallites that are lessthan 10 micrometer in size. In some embodiments, the composite matrix iscomposed of crystallites that are less than 1 micrometer in size.

In some embodiments, the reaction vessel is purged with an inert gas togenerate the inert atmosphere. In some embodiments, the inert gascomprises argon, nitrogen, or helium. In some embodiments, the reactionvessel is subjected to at least one cycle of applying a vacuum andflushing the reaction vessel with an inert gas to remove oxygen from thereaction vessel.

In some embodiments, x is 0. In some embodiments, the composite matrixcomprises WB₄. In some embodiments, the ratio of B to W is between about11.9 and about 9 equivalents of B to 1 equivalent of W. In someembodiments, the ratio of B to W is about 11.6, about 11, about 10.5,about 10, about 9.5, or about 9 equivalents of B to 1 equivalent of W.In some embodiments, the composite matrix is formed with a W to B ratioof 1:11.6. In some embodiments, the composite matrix has oxidationresistance below 450° C. In some embodiments, the composite matrix isformed with a W to B ratio of 1:10.5. In some embodiments, the compositematrix is formed with a W to B ratio of 1:9.0. In some embodiments, thecomposite matrix has oxidation resistance below 465° C. In someembodiments, the composite matrix has a density at or above 4.0 g/cm3.

In some embodiments, x is from 0.001 to 0.999. In some embodiments, x is0.201-0.400. In some embodiments, x is 0.401-0.600. In some embodiments,x is 0.601-0.800. In some embodiments, x is 0.801-0.999.

In some embodiments, the ratio of B to W and M is less than 5equivalents of B to 1 equivalent of W and M. In some embodiments, M isat least one element selected from the group: vanadium (V), chromium(Cr), niobium (Nb), molybdenum (Mo), tantalum (Ta), and rhenium (Re). Insome embodiments, the composite matrix comprises W_(1-x)V_(x)B₄. In someembodiments, the composite matrix comprises W_(1-x)Cr_(x)B₄. In someembodiments, the composite matrix comprises W_(1-x)Nb_(x)B₄. In someembodiments, the composite matrix comprises W_(1-x)Mo_(x)B₄. In someembodiments, the composite matrix comprises W_(1-x)Ta_(x)B₄. In someembodiments, the composite matrix comprises W_(1-x)Re_(x)B₄.

Disclosed herein is a composite matrix comprising a compound of Formula(I):W_(1-x)M_(x)B₄  (I)

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group: vanadium (V),        chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum (Ta), and        rhenium (Re); and    -   x is from 0.001 to 0.999.

In some embodiments, x is 0.001-0.200. In some embodiments, x is0.201-0.400. In some embodiments, x is 0.401-0.600. In some embodiments,x is 0.601-0.800. In some embodiments, x is 0.801-0.999. In someembodiments, the composite matrix is W_(1-x)V_(x)B₄. In someembodiments, the composite matrix is W_(1-x)Cr_(x)B₄. In someembodiments, the composite matrix is W_(1-x)Nb_(x)B₄. In someembodiments, the composite matrix is W_(1-x)Mo_(x)B₄. In someembodiments, the composite matrix is W_(1-x)Ta_(x)B₄. In someembodiments, the composite matrix is W_(1-x)Re_(x)B₄.

Disclosed herein is a composite matrix produced by any of the methodsdisclosed herein.

Disclosed herein is a tool comprising a composite matrix produced by anyof the methods disclosed herein.

Described herein is a method of preparing a composite matrix comprising:combining an amount of W with an amount of B and optionally M togenerate the composite matrix, wherein the ratio of B to W and M is lessthan 12 equivalents of B to 1 equivalent of W and M; and the compositematrix comprises: W_(1-x)M_(x)B₄ wherein: W is tungsten; B is boron; Mis at least one element selected from the group of titanium (Ti),vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co),nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb),molybdenum (Mo), ruthenium (Ru), hafnium (Hf), tantalum (Ta), rhenium(Re), yttrium (Y), osmium (Os), iridium (Ir), lithium (Li) and aluminum(Al); and x is from 0 to 0.999. In some embodiments, the method furthercomprising i) mixing W, B, and optionally M to generate a mixture, ii)transferring the mixture to a reaction vessel, and iii) heating themixture to a temperature sufficient to induce a reaction between W, B,and optionally M to generate the composite matrix. In some embodiments,at least 10% of the atmospheric oxygen is removed from the reactionvessel. In some embodiments, the mixture is heated to a temperaturebetween about 1200° C. and about 2200° C. In some embodiments, themixture is heated for about 15 minutes, 90 minutes, 120 minutes, 180minutes, 240 minutes, 360 minutes, or more. In some embodiments, themixture is heated by an induction furnace or conventional furnace. Insome embodiments, M is at least one element selected from the group:vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum(Ta), and rhenium (Re). In some embodiments, x is 0. In someembodiments, the ratio of B to W is between about 11.9 and about 9equivalents of B to 1 equivalent of W. In some embodiments, x is from0.001 to 0.999. In some embodiments, the ratio of B to W and M is lessthan 5 equivalents of B to 1 equivalent of W and M. In some embodiments,the reaction vessel and reaction mixture is separated by a metal liner.In some embodiments, the composite matrix is a crystalline solidcharacterized by at least one X-ray diffraction pattern reflection at a2 theta of about 24.2. In some embodiments, the crystalline solid isfurther characterized by at least one X-ray diffraction patternreflection at a 2 theta of about 34.5 or about 45.1. Disclosed herein isa method of producing a thermodynamically stable tungsten tetraboridecomposite matrix, the method comprising: a) adding into a compressionchamber a mixture of boron (B) and tungsten (W), wherein the ratio ofboron to tungsten is between 4 and 11.9 equivalents of boron to 1equivalent of tungsten; b) compressing the mixture to generate acompressed raw mixture; c) adding the compressed raw mixture to areaction vessel; d) generating an inert atmosphere within the reactionvessel by applying a vacuum to the reaction vessel, flushing thereaction vessel with inert gas, or a combination thereof; and e) heatingthe reaction vessel to a temperature of between about 1200° C. and about2200° C. to generate the thermodynamically stable WB₄ composite matrix.In some embodiments, the compressed raw mixture is heated by aninduction furnace or a conventional furnace. In some embodiments, thereaction vessel and reaction mixture is separated by a metal liner. Insome embodiments, the composite matrix is a crystalline solidcharacterized by at least one X-ray diffraction pattern reflection at a2 theta of about 24.2. In some embodiments, the crystalline solid isfurther characterized by at least one X-ray diffraction patternreflection at a 2 theta of about 34.5 or about 45.1. Disclosed herein isa tool comprising a composite matrix produced by the methods describedherein.

In certain embodiments, described herein are methods of making acomposite matrix comprising tungsten tetraboride with a reduced ornon-detectable amount of metal side products (or by-products) (e.g.,less than 20%, 15%, 10%, 5%, 4%, 3%, 2%, 1%, 0.5% or less of thecomposite is metal side products). In some embodiments, also describedherein are methods of manufacturing a composite matrix comprisingtungsten tetraboride with a ratio of less than 12 equivalents of boronto 1 equivalent of tungsten. Further disclosed herein, are tungstentetraboride alloys that utilize less than 5 equivalents of boron to 1equivalent of tungsten and metal. In some embodiments, the tungstentetraboride composite or the tungsten tetraboride alloys are applied toa tool or abrasive material.

Metal Boride Composite Matrix

Disclosed herein is a composite matrix comprising a compound of Formula(I):W_(1-x)M_(x)B₄  (I)

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group: vanadium (V),        chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum (Ta), and        rhenium (Re); and    -   x is from 0.001 to 0.999.

In some embodiments, the composite matrix is W_(1-x)M_(x)B₄ and preparedwith a ratio of all metal atoms to boron atoms from about 1 to 4 toabout 1 to 5. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.0. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.1. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.2. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.3. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.4. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.5. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.6. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.7. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.8. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 4.9. In some embodiments, the composite matrix isW_(1-x)M_(x)B₄ and prepared with a ratio of all metal atoms to boronatoms of about 1 to 5.0.

In some embodiments of a composite matrix described herein, or preparedby the methods herein, x has a value within the range 0.001 to 0.999,inclusively. In some embodiments, x has a value within the range 0.005to 0.99, 0.01 to 0.95, 0.05 to 0.9, 0.1 to 0.9, 0.001 to 0.6, 0.005 to0.6, 0.01 to 0.6, 0.05 to 0.6, 0.1 to 0.6, 0.2 to 0.6, 0.3 to 0.6, 0.4to 0.6, 0.001 to 0.55, 0.005 to 0.55, 0.01 to 0.55, 0.05 to 0.55, 0.1 to0.55, 0.2 to 0.55, 0.3 to 0.55, 0.4 to 0.55, 0.45 to 0.55, 0.001 to 0.5,0.005 to 0.5, 0.01 to 0.5, 0.05 to 0.5, 0.1 to 0.5, 0.2 to 0.5, 0.3 to0.5, 0.4 to 0.5, 0.5 to 0.55, 0.45 to 0.5, 0.001 to 0.4, 0.005 to 0.4,0.01 to 0.4, 0.05 to 0.4, 0.1 to 0.4, 0.2 to 0.4, 0.001 to 0.3, 0.005 to0.3, 0.01 to 0.3, 0.05 to 0.3, 0.1 to 0.3, 0.001 to 0.2, 0.005 to 0.2,0.01 to 0.2, 0.05 to 0.2, or 0.1 to 0.2, inclusively. In someembodiments, x has a value within the range 0.1 to 0.9, inclusively. Insome embodiments, x has a value within the range 0.001 to 0.6, 0.005 to0.6, 0.001 to 0.4, or 0.001 to 0.2, inclusively. In some embodiments, xhas a value within the range 0.001 to 0.6, inclusively. In someembodiments, x has a value within the range 0.001 to 0.5, inclusively.In some embodiments, x has a value within the range 0.001 to 0.4,inclusively. In some embodiments, x has a value within the range 0.001to 0.3, inclusively. In some embodiments, x has a value within the range0.001 to 0.2, inclusively. In some embodiments, x has a value within therange 0.01 to 0.6, inclusively. In some embodiments, x has a valuewithin the range 0.01 to 0.5, inclusively. In some embodiments, x has avalue within the range 0.01 to 0.4, inclusively. In some embodiments, xhas a value within the range 0.01 to 0.3, inclusively. In someembodiments, x has a value within the range 0.01 to 0.2, inclusively. Insome embodiments, x has a value within the range 0.1 to 0.8,inclusively. In some embodiments, x has a value within the range 0.1 to0.7, inclusively. In some embodiments, x has a value within the range0.1 to 0.6, inclusively. In some embodiments, x has a value within therange 0.1 to 0.5, inclusively. In some embodiments, x has a value withinthe range 0.1 to 0.4, inclusively. In some embodiments, x has a valuewithin the range 0.1 to 0.3, inclusively. In some embodiments, x has avalue within the range 0.1 to 0.2, inclusively. In some embodiments, xhas a value within the range 0.2 to 0.8, inclusively. In someembodiments, x has a value within the range 0.2 to 0.7, inclusively. Insome embodiments, x has a value within the range 0.2 to 0.6,inclusively. In some embodiments, x has a value within the range 0.2 to0.5, inclusively. In some embodiments, x has a value within the range0.2 to 0.4, inclusively. In some embodiments, x has a value within therange 0.2 to 0.3, inclusively. In some embodiments, x has a value withinthe range 0.3 to 0.8, inclusively. In some embodiments, x has a valuewithin the range 0.3 to 0.7, inclusively. In some embodiments, x has avalue within the range 0.3 to 0.6, inclusively. In some embodiments, xhas a value within the range 0.3 to 0.5, inclusively. In someembodiments, x has a value within the range 0.3 to 0.4, inclusively. Insome embodiments, x has a value within the range 0.4 to 0.8,inclusively. In some embodiments, x has a value within the range 0.4 to0.7, inclusively. In some embodiments, x has a value within the range0.4 to 0.6, inclusively. In some embodiments, x has a value within therange 0.4 to 0.5, inclusively.

In some embodiments of a composite matrix described herein, or preparedby the methods herein, x is at least 0.001 and less than 0.999. In someembodiments, x is at least 0.001 and less than 0.9. In some embodiments,x is at least 0.001 and less than 0.6. In some embodiments, x is atleast 0.001 and less than 0.5. In some embodiments, x is at least 0.001and less than 0.4. In some embodiments, x is at least 0.001 and lessthan 0.3. In some embodiments, x is at least 0.001 and less than 0.2. Insome embodiments, x is at least 0.001 and less than 0.05. In someembodiments, x is at least 0.01 and less than 0.5. In some embodiments,x is at least 0.01 and less than 0.4. In some embodiments, x is at least0.01 and less than 0.3. In some embodiments, x is at least 0.01 and lessthan 0.2. In some embodiments, x is at least 0.1 and less than 0.5. Insome embodiments, x is at least 0.1 and less than 0.4. In someembodiments, x is at least 0.1 and less than 0.3. In some embodiments, xis at least 0.1 and less than 0.2.

In some embodiments of a composite matrix described herein, or preparedby the methods herein, x has a value of about 0.001, 0.005, 0.01, 0.05,0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45,0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57,0.58, 0.59, 0.6, 0.65, 0.7, 0.8, 0.9, 0.95, 0.99, or about 0.999. Insome embodiments, x has a value of about 0.001. In some embodiments, xhas a value of about 0.005. In some embodiments, x has a value of about0.01. In some embodiments, x has a value of about 0.05. In someembodiments, x has a value of about 0.1. In some embodiments, x has avalue of about 0.15. In some embodiments, x has a value of about 0.2. Insome embodiments, x has a value of about 0.3. In some embodiments, x hasa value of about 0.4. In some embodiments, x has a value of about 0.41.In some embodiments, x has a value of about 0.42. In some embodiments, xhas a value of about 0.43. In some embodiments, x has a value of about0.44. In some embodiments, x has a value of about 0.45. In someembodiments, x has a value of about 0.46. In some embodiments, x has avalue of about 0.47. In some embodiments, x has a value of about 0.48.In some embodiments, x has a value of about 0.49. In some embodiments, xhas a value of about 0.5. In some embodiments, x has a value of about0.51. In some embodiments, x has a value of about 0.52. In someembodiments, x has a value of about 0.53. In some embodiments, x has avalue of about 0.54. In some embodiments, x has a value of about 0.55.In some embodiments, x has a value of about 0.56. In some embodiments, xhas a value of about 0.57. In some embodiments, x has a value of about0.58. In some embodiments, x has a value of about 0.59. In someembodiments, x has a value of about 0.6. In some embodiments, x has avalue of about 0.7. In some embodiments, x has a value of about 0.8. Insome embodiments, x has a value of about 0.9. In some embodiments, x hasa value of about 0.99.

In some embodiments of a composite matrix described herein, or preparedby the methods herein, x is 0.001-0.200. In some embodiments, x is0.201-0.400. In some embodiments, x is 0.401-0.600. In some embodiments,x is 0.601-0.800. In some embodiments, x is 0.801-0.999.

In some embodiments of a composite matrix described herein, or preparedby the methods herein, x is about 0.05. In some embodiments, x is about0.25. In some embodiments, x is about 0.50. In some embodiments, x isabout 0.75. In some embodiments, x is about 0.80. In some embodiments, xis about 0.85. In some embodiments, x is about 0.90. In someembodiments, x is about 0.95.

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, is comprised of a metal side product is less than20%, 15%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%,0.05%, or 0.01% relative to the percentage of the composite matrix. Insome embodiments, the metal side product is tungsten diboride (WB₂) ortungsten monoboride (WB). In some embodiments, the metal side product isa non-tungsten metal boride. In some embodiments, the non-tungsten metalboride is TiB₂, ZrB₂, HfB₂, VB, VB₂, NbB₂, NbB₂, CrB, CrB₂, Cr₂B, Cr₃B₄,Cr₄B, Cr₅B₃, MoB, MoB₂, Mo₂B₄, Mo₂B₅, MnB, MnB₂, MNB₄, Mn₂B, Mn₄B,Mn₃B₄, ReB₂, Re₃B, Re₇B₂, FeB, Fe₂B, RuB₂, Ru₂B₃, OsB, Os₂B₃, OsB₂, CoB,Co₂B, IrB, Ir₂B, NiB, Ni₂B, Ni₃B, CuB, or ZnB.

In some embodiments, at least one allotrope of elemental boron ispresent in the composite matrix. Allotropes of boron include thefollowing states of boron: alpha rhombohedral, alpha tetragonal, betarhombohedral, beta tetragonal, orthorhombic (gamma), borophen,borospherene and amorphous boron.

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, contain a compound of Formulas (I-IV), boron, and ametal side product. In some embodiments, a compound of Formulas (I-IV)and boron account for 80% or more of the composite matrix's weight. Insome embodiments, a compound of Formulas (I-IV) and boron account for85% or more of the composite matrix's weight. In some embodiments, acompound of Formulas (I-IV) and boron account for 88% or more of thecomposite matrix's weight. In some embodiments, a compound of Formulas(I-IV) and boron account for 90% or more of the composite matrix'sweight. In some embodiments, a compound of Formulas (I-IV) and boronaccount for 91% or more of the composite matrix's weight. In someembodiments, a compound of Formulas (I-IV) and boron account for 92% ormore of the composite matrix's weight. In some embodiments, a compoundof Formulas (I-IV) and boron account for 93% or more of the compositematrix's weight. In some embodiments, a compound of Formulas (I-IV) andboron account for 94% or more of the composite matrix's weight. In someembodiments, a compound of Formulas (I-IV) and boron account for 95% ormore of the composite matrix's weight. In some embodiments, a compoundof Formulas (I-IV) and boron account for 96% or more of the compositematrix's weight. In some embodiments, a compound of Formulas (I-IV) andboron account for 97% or more of the composite matrix's weight. In someembodiments, a compound of Formulas (I-IV) and boron account for 98% ormore of the composite matrix's weight. In some embodiments, a compoundof Formulas (I-IV) and boron account for 99% or more of the compositematrix's weight. In some embodiments, a compound of Formulas (I-IV) andboron account for 99.5% or more of the composite matrix's weight. Insome embodiments, a compound of Formulas (I-IV) and boron account for99.9% or more of the composite matrix's weight. In some embodiments, acompound of Formulas (I-IV) and boron account for 99.95% or more of thecomposite matrix's weight. In some embodiments, a compound of Formulas(I-IV) and boron account for 99.99% or more of the composite matrix'sweight.

In some embodiments, in a composite matrix described herein, or preparedby the methods herein, the percentage of the composite matrix of Formula(I) and boron relative to the composite material is at least 80%, 85%,88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%,99.95%, or 99.99%. In some embodiments, in a composite matrix describedherein, or prepared by the methods herein, the percentage of thecomposite matrix of Formula (II) and boron relative to the compositematerial is at least 80%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%,97%, 98%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%. In some embodiments, ina composite matrix described herein, or prepared by the methods herein,the percentage of the composite matrix of Formula (III) and boronrelative to the composite material is at least 80%, 85%, 88%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%.In some embodiments, in a composite matrix described herein, or preparedby the methods herein, the percentage of the composite matrix of Formula(IV) and boron relative to the composite material is at least 80%, 85%,88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%,99.95%, or 99.99%.

In some embodiments, the composite matrix is W_(1-x)V_(x)B₄. In someembodiments, the composite matrix is W_(0.95)V_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)V_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)V_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)V_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)V_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)V_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)V_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)V_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)V_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)V_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)V_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)V_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)V_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)V_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)V_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)V_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)V_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)V_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)V_(0.95)B₄.

In some embodiments, the composite matrix is W_(1-x)Cr_(x)B₄. In someembodiments, the composite matrix is W_(0.95)Cr_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)Cr_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)Cr_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)Cr_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)Cr_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)Cr_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)Cr_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)Cr_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)Cr_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)Cr_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)Cr_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)Cr_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)Cr_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)Cr_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)Cr_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)Cr_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)Cr_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)Cr_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)Cr_(0.95)B₄.

In some embodiments, the composite matrix is W_(1-x)Nb_(x)B₄. In someembodiments, the composite matrix is W_(0.95)Nb_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)Nb_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)Nb_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)Nb_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)Nb_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)Nb_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)Nb_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)Nb_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)Nb_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)Nb_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)Nb_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)Nb_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)Nb_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)Nb_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)Nb_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)Nb_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)Nb_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)Nb_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)Nb_(0.95)B₄.

In some embodiments, the composite matrix is W_(1-x)Mo_(x)B₄. In someembodiments, the composite matrix is W_(0.95)Mo_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)Mo_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)Mo_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)Mo_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)Mo_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)Mo_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)Mo_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)Mo_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)Mo_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)Mo_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)Mo_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)Mo_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)Mo_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)Mo_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)Mo_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)Mo_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)Mo_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)Mo_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)Mo_(0.95)B₄.

In some embodiments, the composite matrix is W_(1-x)Ta_(x)B₄. In someembodiments, the composite matrix is W_(0.95)Ta_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)Ta_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)Ta_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)Ta_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)Ta_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)Ta_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)Ta_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)Ta_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)Ta_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)Ta_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)Ta_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)Ta_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)Ta_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)Ta_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)Ta_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)Ta_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)Ta_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)Ta_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)Ta_(0.95)B₄.

In some embodiments, the composite matrix is W_(1-x)Re_(x)B₄. In someembodiments, the composite matrix is W_(0.95)Re_(0.05)B₄. In someembodiments, the composite matrix is W_(0.90)Re_(0.10)B₄. In someembodiments, the composite matrix is W_(0.85)Re_(0.15)B₄. In someembodiments, the composite matrix is W_(0.80)Re_(0.20)B₄. In someembodiments, the composite matrix is W_(0.75)Re_(0.25)B₄. In someembodiments, the composite matrix is W_(0.70)Re_(0.30)B₄. In someembodiments, the composite matrix is W_(0.65)Re_(0.35)B₄. In someembodiments, the composite matrix is W_(0.60)Re_(0.40)B₄. In someembodiments, the composite matrix is W_(0.55)Re_(0.45)B₄. In someembodiments, the composite matrix is W_(0.50)Re_(0.50)B₄. In someembodiments, the composite matrix is W_(0.45)Re_(0.55)B₄. In someembodiments, the composite matrix is W_(0.40)Re_(0.60)B₄. In someembodiments, the composite matrix is W_(0.35)Re_(0.65)B₄. In someembodiments, the composite matrix is W_(0.30)Re_(0.70)B₄. In someembodiments, the composite matrix is W_(0.25)Re_(0.75)B₄. In someembodiments, the composite matrix is W_(0.20)Re_(0.80)B₄. In someembodiments, the composite matrix is W_(0.15)Re_(0.85)B₄. In someembodiments, the composite matrix is W_(0.10)Re_(0.90)B₄. In someembodiments, the composite matrix is W_(0.05)Re_(0.95)B₄.

In some embodiments, the hardness described herein is measured by aVickers hardness test. In some embodiments, the hardness is measuredunder a load of 0.49 Newton (N).

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, has a hardness of about 10 to about 70 GPa. In someembodiments, a composite matrix described herein has a hardness of about10 to about 60 GPa, about 10 to about 50 GPa, about 10 to about 40 GPa,about 10 to about 30 GPa, about 20 to about 70 GPa, about 20 to about 60GPa, about 20 to about 50 GPa, about 20 to about 40 GPa, about 20 toabout 30 GPa, about 30 to about 70 GPa, about 30 to about 60 GPa, about30 to about 50 GPa, about 30 to about 45 GPa, about 30 to about 40 GPa,about 30 to about 35 GPa, about 35 to about 70 GPa, about 35 to about 60GPa, about 35 to about 50 GPa, about 35 to about 40 GPa, about 40 toabout 70 GPa, about 40 to about 60 GPa, about 40 to about 50 GPa, about45 to about 60 GPa or about 45 to about 50 GPa. In some embodiments, acomposite matrix described herein has a hardness of about 30 to about 50GPa, about 30 to about 45 GPa, about 30 to about 40 GPa, about 30 toabout 35 GPa, about 35 to about 50 GPa, about 35 to about 40 GPa, about40 to about 50 GPa, or about 45 to about 50 GPa.

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, has a hardness of about 10 GPa, about 15 GPa, about20 GPa, about 25 GPa, about 30 GPa, about 31 GPa, about 32 GPa, about 33GPa, about 34 GPa, about 35 GPa, about 36 GPa, about 37 GPa, about 38GPa, about 39 GPa, about 40 GPa, about 41 GPa, about 42 GPa, about 43GPa, about 44 GPa, about 45 GPa, about 46 GPa, about 47 GPa, about 48GPa, about 49 GPa, about 50 GPa, about 51 GPa, about 52 GPa, about 53GPa, about 54 GPa, about 55 GPa, about 56 GPa, about 57 GPa, about 58GPa, about 59 GPa, about 60 GPa or higher. In some embodiments, acomposite matrix described herein has a hardness of about 10 GPa orhigher. In some embodiments, a composite matrix described herein has ahardness of about 15 GPa or higher. In some embodiments, a compositematrix described herein has a hardness of about 20 GPa or higher. Insome embodiments, a composite matrix described herein has a hardness ofabout 25 GPa or higher. In some embodiments, a composite matrixdescribed herein has a hardness of about 30 GPa or higher. In someembodiments, a composite matrix described herein has a hardness of about31 GPa or higher. In some embodiments, a composite matrix describedherein has a hardness of about 32 GPa or higher. In some embodiments, acomposite matrix described herein has a hardness of about 33 GPa orhigher. In some embodiments, a composite matrix described herein has ahardness of about 34 GPa or higher. In some embodiments, a compositematrix described herein has a hardness of about 35 GPa or higher. Insome embodiments, a composite matrix described herein has a hardness ofabout 36 GPa or higher. In some embodiments, a composite matrixdescribed herein has a hardness of about 37 GPa or higher. In someembodiments, a composite matrix described herein has a hardness of about38 GPa or higher. In some embodiments, a composite matrix describedherein has a hardness of about 39 GPa or higher. In some embodiments, acomposite matrix described herein has a hardness of about 40 GPa orhigher. In some embodiments, a composite matrix described herein has ahardness of about 41 GPa or higher. In some embodiments, a compositematrix described herein has a hardness of about 42 GPa or higher. Insome embodiments, a composite matrix described herein has a hardness ofabout 43 GPa or higher. In some embodiments, a composite matrixdescribed herein has a hardness of about 44 GPa or higher. In someembodiments, a composite matrix described herein has a hardness of about45 GPa or higher. In some embodiments, a composite matrix describedherein has a hardness of about 46 GPa or higher. In some embodiments, acomposite matrix described herein has a hardness of about 47 GPa orhigher. In some embodiments, a composite matrix described herein has ahardness of about 48 GPa or higher. In some embodiments, a compositematrix described herein has a hardness of about 49 GPa or higher. Insome embodiments, a composite matrix described herein has a hardness ofabout 50 GPa or higher. In some embodiments, a composite matrixdescribed herein has a hardness of about 51 GPa or higher. In someembodiments, a composite matrix described herein has a hardness of about52 GPa or higher. In some embodiments, a composite matrix describedherein has a hardness of about 53 GPa or higher. In some embodiments, acomposite matrix described herein has a hardness of about 54 GPa orhigher. In some embodiments, a composite matrix described herein has ahardness of about 55 GPa or higher. In some embodiments, a compositematrix described herein has a hardness of about 56 GPa or higher. Insome embodiments, a composite matrix described herein has a hardness ofabout 57 GPa or higher. In some embodiments, a composite matrixdescribed herein has a hardness of about 58 GPa or higher. In someembodiments, a composite matrix described herein has a hardness of about59 GPa or higher. In some embodiments, a composite matrix describedherein has a hardness of about 60 GPa or higher.

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, has a grain size or crystallite size of about 20 μmor less. In some embodiments, the composite matrix has a grain size orcrystallite size of about 15 μm or less, about 12 μm or less, about 10μm or less, about 8 μm or less, about 5 μm or less, about 2 μm or lessor about 1 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 15 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 12 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 10 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 9 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 8 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 7 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 6 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 5 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 4 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 3 μm or less. In some embodiments, the composite matrix has agrain size or crystallite size of about 2 μm or less. In someembodiments, the composite matrix has a grain size or crystallite sizeof about 1 μm or less.

In some embodiments, the grain size is an averaged grain size. In someembodiments, the crystallite size is an averaged crystallite size. Insome embodiments, a composite matrix described herein, or prepared bythe methods herein, has an averaged grain size or averaged crystallitesize of about 100 μm or less, 50 μm or less, 40 μm or less, 30 μm orless, 20 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, 5 μm orless, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less,

In some embodiments, a composite matrix described herein, or prepared bythe methods herein, is a densified composite matrix. In someembodiments, the density is 12.0 g/cm³ or less. In some embodiments, thedensity is 9.0 g/cm³ or less. In some embodiments, the density is 8.0g/cm³ or less. In some embodiments, the density is 7.0 g/cm³ or less. Insome embodiments, the density is 6.0 g/cm³ or less. In some embodiments,the density is 5.0 g/cm³ or less. In some embodiments, the density is4.0 g/cm³ or less. In some embodiments, a composite matrix describedherein has a density of or between 4.0-9.0 g/cm³. In some embodiments, acomposite matrix described herein has a density of or between 4.0-7.0g/cm³. In some embodiments, a composite matrix described herein has adensity of or between 4.0-6.0 g/cm³. In some embodiments, a compositematrix described herein has a density of or between 5.0-6.0 g/cm³.

In some embodiments, a composite matrix comprising WB₄ has a density of10.0 g/cm³ or less. In some embodiments, a composite matrix comprisingWB₄ has a density of 9.0 g/cm³ or less. In some embodiments, a compositematrix comprising WB₄ has a density of 8.5 g/cm³ or less. In someembodiments, a composite matrix comprising WB₄ has a density of 8.0g/cm³ or less. In some embodiments, a composite matrix comprising WB₄has a density of 7.5 g/cm³ or less. In some embodiments, a compositematrix comprising WB₄ has a density of 7.0 g/cm³ or less. In someembodiments, a composite matrix comprising WB₄ has a density of 6.5g/cm³ or less. In some embodiments, a composite matrix comprising WB₄has a density of 6.0 g/cm³ or less. In some embodiments, a compositematrix comprising WB₄ has a density of 5.5 g/cm³ or less. In someembodiments, a composite matrix comprising WB₄ has a density of 5.0g/cm³ or less. In some embodiments, a composite matrix comprising WB₄has a density of 4.5 g/cm³ or less.

In some embodiments, the composite matrix described herein, or preparedby the methods herein, is resistant to oxidation. In some embodiments,the composite matrix is resistant to oxidation below 400° C. In someembodiments, the composite matrix is resistant to oxidation below 410°C. In some embodiments, the composite matrix is resistant to oxidationbelow 420° C. In some embodiments, the composite matrix is resistant tooxidation below 440° C. In some embodiments, the composite matrix isresistant to oxidation below 450° C. In some embodiments, the compositematrix is resistant to oxidation below 460° C. In some embodiments, thecomposite matrix is resistant to oxidation below 465° C. In someembodiments, the composite matrix is resistant to oxidation below 475°C. In some embodiments, the composite matrix is resistant to oxidationbelow 490° C. In some embodiments, the composite matrix is resistant tooxidation below 500° C. In some embodiments, the composite matrix isresistant to oxidation below 550° C. In some embodiments, the compositematrix is resistant to oxidation below 600° C. In some embodiments, thecomposite matrix is resistant to oxidation below 650° C. In someembodiments, the composite matrix is resistant to oxidation below 700°C. In some embodiments, the composite matrix is resistant to oxidationbelow 800° C. In some embodiments, the composite matrix is resistant tooxidation below 900° C.

In some embodiments, a composite material described herein is resistantto oxidation. In some embodiments, a composite material described hereinhas anti-oxidation property. For example, when the composite material iscoated on the surface of a tool, the composite material reduces the rateof oxidation of the tool in comparison to a tool not coated with thecomposite material. In an alternative example, when the compositematerial is coated on the surface of a tool, the composite materialprevents oxidation of the tool in comparison to a tool not coated withthe composite material. In some embodiments, the composite materialinhibits the formation of oxidation or reduces the rate of oxidation. Insome embodiments, a coating of the composite matrix reduced the rate ofoxidation of the tool as compared to the uncoated tool. In someembodiments, the composite matrix reduces the rate of oxidation by atleast 1%, at least 2%, at least 3%, least 4%, at least 5%, at least 6%,at least 7%, at least 8%, at least 9%, at least 10%, at least 15%, atleast 20%, at least 25%, at least 30%, at least 35 at least 40%, atleast 45%, at least 50%, at least 55%, at least 60%, at least 65%, atleast 70%, at least 75%, at least 80%, or at least 90%.

In some embodiments, the unit cell a composite matrix described hereinis hexagonal as determined and characterized by X-ray diffraction. Insome embodiments, the unit cell a composite matrix described herein isP6₃/mmm or P6₃/mmc. In some embodiments, the unit cell of the compositematrix is hexagonal and the length of a is between 5.100 and 5.300 Å,where a is the shortest length between two adjacent vertices in the unitcell, and the length of c is between 6.200 and 6.500 Å, where c is thelongest length between two adjacent vertices in the unit cell.

In some embodiments, a composite matrix W_(1-x)Ta_(x)B₄ is hexagonal andthe length of a is between 5.150 and 5.300 Å, and the length of c isbetween 6.300 and 6.450 Å.

In some embodiments, a composite matrix described herein comprises asolid solution phase. In some embodiments, a composite materialdescribed herein forms a solid solution.

Methods of Manufacture

Disclosed herein, in certain embodiments, is a method of preparing acomposite matrix, in which the method comprises:

-   -   combining a sufficient amount of W with an amount of B and        optionally M to generate the composite matrix, wherein the ratio        of B to W and M is less than 12 equivalents of B to 1 equivalent        of W and M; and the composite matrix comprises:        W_(1-x)M_(x)B₄

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al); and    -   x is from 0 to 0.999

In some embodiments, the combining step comprises i) mixing W, B, andoptionally M to generate a mixture, ii) transferring the mixture to areaction vessel, and iii) heating the mixture to a temperaturesufficient to induce a reaction between W, B, and optionally M togenerate the composite matrix. In some embodiments, the combining stepcomprises i) mixing W, and B to generate a mixture, ii) transferring themixture to a reaction vessel, and iii) heating the mixture to atemperature sufficient to induce a reaction between W and B to generatethe composite matrix. In some embodiments, the combining step comprisesi) mixing W, B, and M to generate a mixture, ii) transferring themixture to a reaction vessel, and iii) heating the mixture to atemperature sufficient to induce a reaction between W, B, and M togenerate the composite matrix.

In some embodiments, the combining step comprises i) mixing W, B, andoptionally M to generate a mixture, ii) transferring the mixture to areaction vessel, iii) arc melting the mixture to until the mixture ismelted; and iv) cooling the mixture.

Also disclosed herein, in certain embodiments, is a method of producinga composite matrix of Formula (II):W_(1-x)M_(x)B₄  (II)

wherein:

-   -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is from 0.001 to 0.999; and    -   wherein the method comprises:    -   a) adding into a compression chamber a mixture of boron,        tungsten, and M, wherein the ratio of boron to tungsten and M is        between 3.5 and 8.0 equivalents of boron to 1 equivalent of        tungsten and M;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the composite matrix of        Formula (II).

Further disclosed herein, in certain embodiments, is a method ofproducing a composite material comprising a composite matrix of Formula(III):W_(1-x)M_(x)B₄  (III)

-   -   wherein the percentage of the composite matrix of Formula (III)        and boron relative to the composite material is at least 95%,        wherein,    -   W is tungsten;    -   B is boron;    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is from 0 to 0.999; and    -   wherein the method comprises:    -   a) adding into a compression chamber a mixture of boron,        tungsten, and optionally M, wherein the ratio of boron to        tungsten and optionally M is less than 12.0 equivalents of boron        to 1 equivalent of tungsten and optionally M;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) partially lining the interior of the reaction vessel with an        electric insulator to generate an insulated reaction vessel;    -   d) adding the compressed raw mixture to the insulated reaction        vessel;    -   e) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the insulated reaction vessel, flushing the        insulated reaction vessel with inert gas, or a combination        thereof;    -   f) arc melting the compressed raw mixture until at least 95% or        more of the compressed raw mixture is melted; and    -   g) cooling the insulated reaction vessel, thereby generating the        composite material comprising the composite matrix of Formula        (III).

Disclosed herein, in certain embodiments, is a method of preparing acomposite matrix, in which the method comprises:

-   -   combining a sufficient amount of W with an amount of Z and M to        generate the composite matrix, wherein the ratio of Z to W and M        is less than 12 equivalents of B to 1 equivalent of W and M; and        the composite matrix comprises:        W_(1-x)M_(x)Z_(y)

wherein:

-   -   W is tungsten;    -   Z is boron (B), silicon (Si) or beryllium (Be);    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is at least 0.001 and less than 0.999; and    -   y is at least 3.5.

Also disclosed herein, in certain embodiments, is a method of producinga composite matrix of Formula (IV):W_(1-x)M_(x)Z_(y)  (IV)

wherein:

-   -   W is tungsten;    -   Z is boron (B), silicon (Si) or beryllium (Be);    -   M is at least one element selected from the group of titanium        (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium        (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium (Os),        iridium (Ir), lithium (Li) and aluminum (Al);    -   x is from 0.001 to 0.999;    -   y is from 3.5 to 12.0; and    -   wherein the method comprises:    -   a) adding into a compression chamber a mixture of boron,        tungsten, and M, wherein the ratio of boron to tungsten and M is        between 3.5 and 5.0 equivalents of boron to 1 equivalent of        tungsten and M;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the composite matrix of        Formula (IV).

In some embodiments, x is 0 and the composite matrix comprises WB₄. Insome embodiments, the ratio of B to W is between about 15.0 and about 4equivalents of B to 1 equivalent of W. In some embodiments, the ratio ofB to W is between about 12 and about 4 equivalents of B to 1 equivalentof W. In some embodiments, the ratio of B to W is between about 12 andabout 6 equivalents of B to 1 equivalent of W. In some embodiments, theratio of B to W is between about 12 and about 8 equivalents of B to 1equivalent of W. In some embodiments, the ratio of B to W is betweenabout 11.9 and about 9 equivalents of B to 1 equivalent of W. In someembodiments, the ratio of B to W is between about 11 and about 9equivalents of B to 1 equivalent of W. In some embodiments, the ratio ofB to W is between about 10.5 and about 9.5 equivalents of B to 1equivalent of W.

In some embodiments, the ratio of B to W is about 15.0, about 13.0,about 12.0, about 11.9, about 11.8, about 11.6, about 11.4, about 11.2,about 11.0, about 10.8, about 10.7, about 10.6, about 10.5, about 10.4,about 10.3, about 10.2, about 10.1, about 10, about 9.9, about 9.8,about 9.7, about 9.6, about 9.5, about 9.3, about 9.1, about 8.8, about8.5, about 8.2, about 8.0, about 7, about 6, about 5, or about 4equivalents of B to 1 equivalent of W.

In some embodiments, M is at least one element selected from the group:vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum(Ta), and rhenium (Re).

In some embodiments, the ratio of B to W and M is less than 4equivalents of B to 1 equivalent of W and M. In some embodiments, theratio of B to W and M is less than 4.5 equivalents of B to 1 equivalentof W and M. In some embodiments, the ratio of B to W and M is less than4.6 equivalents of B to 1 equivalent of W and M. In some embodiments,the ratio of B to W and M is less than 4.7 equivalents of B to 1equivalent of W and M. In some embodiments, the ratio of B to W and M isless than 4.8 equivalents of B to 1 equivalent of W and M. In someembodiments, the ratio of B to W and M is less than 4.9 equivalents of Bto 1 equivalent of W and M. In some embodiments, the ratio of B to W andM is less than 5 equivalents of B to 1 equivalent of W and M. In someembodiments, the ratio of B to W and M is less than 5.1 equivalents of Bto 1 equivalent of W and M. In some embodiments, the ratio of B to W andM is less than 5.2 equivalents of B to 1 equivalent of W and M. In someembodiments, the ratio of B to W and M is less than 5.3 equivalents of Bto 1 equivalent of W and M. In some embodiments, the ratio of B to W andM is less than 5.4 equivalents of B to 1 equivalent of W and M. In someembodiments, the ratio of B to W and M is less than 5.5 equivalents of Bto 1 equivalent of W and M. In some embodiments, the ratio of B to W andM is less than 6 equivalents of B to 1 equivalent of W and M. In someembodiments, the ratio of B to W and M is less than 10 equivalents of Bto 1 equivalent of W and M.

In some embodiments, x has a value within the range 0.001 to 0.999,inclusively. In some embodiments, x has a value within the range 0.005to 0.99, 0.01 to 0.95, 0.05 to 0.9, 0.1 to 0.9, 0.001 to 0.6, 0.005 to0.6, 0.01 to 0.6, 0.05 to 0.6, 0.1 to 0.6, 0.2 to 0.6, 0.3 to 0.6, 0.4to 0.6, 0.001 to 0.55, 0.005 to 0.55, 0.01 to 0.55, 0.05 to 0.55, 0.1 to0.55, 0.2 to 0.55, 0.3 to 0.55, 0.4 to 0.55, 0.45 to 0.55, 0.001 to 0.5,0.005 to 0.5, 0.01 to 0.5, 0.05 to 0.5, 0.1 to 0.5, 0.2 to 0.5, 0.3 to0.5, 0.4 to 0.5, 0.5 to 0.55, 0.45 to 0.5, 0.001 to 0.4, 0.005 to 0.4,0.01 to 0.4, 0.05 to 0.4, 0.1 to 0.4, 0.2 to 0.4, 0.001 to 0.3, 0.005 to0.3, 0.01 to 0.3, 0.05 to 0.3, 0.1 to 0.3, 0.001 to 0.2, 0.005 to 0.2,0.01 to 0.2, 0.05 to 0.2, or 0.1 to 0.2, inclusively. In someembodiments, x has a value within the range 0.1 to 0.9, inclusively. Insome embodiments, x has a value within the range 0.001 to 0.6, 0.005 to0.6, 0.001 to 0.4, or 0.001 to 0.2, inclusively. In some embodiments, xhas a value within the range 0.001 to 0.6, inclusively. In someembodiments, x has a value within the range 0.001 to 0.5, inclusively.In some embodiments, x has a value within the range 0.001 to 0.4,inclusively. In some embodiments, x has a value within the range 0.001to 0.3, inclusively. In some embodiments, x has a value within the range0.001 to 0.2, inclusively. In some embodiments, x has a value within therange 0.01 to 0.6, inclusively. In some embodiments, x has a valuewithin the range 0.01 to 0.5, inclusively. In some embodiments, x has avalue within the range 0.01 to 0.4, inclusively. In some embodiments, xhas a value within the range 0.01 to 0.3, inclusively. In someembodiments, x has a value within the range 0.01 to 0.2, inclusively. Insome embodiments, x has a value within the range 0.1 to 0.8,inclusively. In some embodiments, x has a value within the range 0.1 to0.7, inclusively. In some embodiments, x has a value within the range0.1 to 0.6, inclusively. In some embodiments, x has a value within therange 0.1 to 0.5, inclusively. In some embodiments, x has a value withinthe range 0.1 to 0.4, inclusively. In some embodiments, x has a valuewithin the range 0.1 to 0.3, inclusively. In some embodiments, x has avalue within the range 0.1 to 0.2, inclusively. In some embodiments, xhas a value within the range 0.2 to 0.8, inclusively. In someembodiments, x has a value within the range 0.2 to 0.7, inclusively. Insome embodiments, x has a value within the range 0.2 to 0.6,inclusively. In some embodiments, x has a value within the range 0.2 to0.5, inclusively. In some embodiments, x has a value within the range0.2 to 0.4, inclusively. In some embodiments, x has a value within therange 0.2 to 0.3, inclusively. In some embodiments, x has a value withinthe range 0.3 to 0.8, inclusively. In some embodiments, x has a valuewithin the range 0.3 to 0.7, inclusively. In some embodiments, x has avalue within the range 0.3 to 0.6, inclusively. In some embodiments, xhas a value within the range 0.3 to 0.5, inclusively. In someembodiments, x has a value within the range 0.3 to 0.4, inclusively. Insome embodiments, x has a value within the range 0.4 to 0.8,inclusively. In some embodiments, x has a value within the range 0.4 to0.7, inclusively. In some embodiments, x has a value within the range0.4 to 0.6, inclusively. In some embodiments, x has a value within therange 0.4 to 0.5, inclusively.

In some embodiments, x is at least 0.001 and less than 0.999. In someembodiments, x is at least 0.001 and less than 0.9. In some embodiments,x is at least 0.001 and less than 0.6. In some embodiments, x is atleast 0.001 and less than 0.5. In some embodiments, x is at least 0.001and less than 0.4. In some embodiments, x is at least 0.001 and lessthan 0.3. In some embodiments, x is at least 0.001 and less than 0.2. Insome embodiments, x is at least 0.001 and less than 0.05. In someembodiments, x is at least 0.01 and less than 0.5. In some embodiments,x is at least 0.01 and less than 0.4. In some embodiments, x is at least0.01 and less than 0.3. In some embodiments, x is at least 0.01 and lessthan 0.2. In some embodiments, x is at least 0.1 and less than 0.5. Insome embodiments, x is at least 0.1 and less than 0.4. In someembodiments, x is at least 0.1 and less than 0.3. In some embodiments, xis at least 0.1 and less than 0.2.

In some embodiments, x has a value of about 0.001, 0.005, 0.01, 0.05,0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45,0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57,0.58, 0.59, 0.6, 0.65, 0.7, 0.8, 0.9, 0.95, 0.99, or about 0.999. Insome embodiments, x has a value of about 0.001. In some embodiments, xhas a value of about 0.005. In some embodiments, x has a value of about0.01. In some embodiments, x has a value of about 0.05. In someembodiments, x has a value of about 0.1. In some embodiments, x has avalue of about 0.15. In some embodiments, x has a value of about 0.2. Insome embodiments, x has a value of about 0.3. In some embodiments, x hasa value of about 0.4. In some embodiments, x has a value of about 0.41.In some embodiments, x has a value of about 0.42. In some embodiments, xhas a value of about 0.43. In some embodiments, x has a value of about0.44. In some embodiments, x has a value of about 0.45. In someembodiments, x has a value of about 0.46. In some embodiments, x has avalue of about 0.47. In some embodiments, x has a value of about 0.48.In some embodiments, x has a value of about 0.49. In some embodiments, xhas a value of about 0.5. In some embodiments, x has a value of about0.51. In some embodiments, x has a value of about 0.52. In someembodiments, x has a value of about 0.53. In some embodiments, x has avalue of about 0.54. In some embodiments, x has a value of about 0.55.In some embodiments, x has a value of about 0.56. In some embodiments, xhas a value of about 0.57. In some embodiments, x has a value of about0.58. In some embodiments, x has a value of about 0.59. In someembodiments, x has a value of about 0.6. In some embodiments, x has avalue of about 0.7. In some embodiments, x has a value of about 0.8. Insome embodiments, x has a value of about 0.9. In some embodiments, x hasa value of about 0.99.

In some embodiments, x is 0.001-0.200. In some embodiments, x is0.201-0.400. In some embodiments, x is 0.401-0.600. In some embodiments,x is 0.601-0.800. In some embodiments, x is 0.801-0.999.

In some embodiments, x is about 0.05. In some embodiments, x is about0.25. In some embodiments, x is about 0.50. In some embodiments, x isabout 0.75. In some embodiments, x is about 0.80. In some embodiments, xis about 0.85. In some embodiments, x is about 0.90. In someembodiments, x is about 0.95.

In some embodiments, y is about 3.5. In some embodiments, y is about3.75. In some embodiments, y is about 4.0. In some embodiments, y isabout 4.25. In some embodiments, y is about 4.5. In some embodiments, yis about 4.75. In some embodiments, y is about 5.0. In some embodiments,y is about 5.5. In some embodiments, y is about 6.0. In someembodiments, y is about 6.5. In some embodiments, y is about 7.0. Insome embodiments, y is about 7.5. In some embodiments, y is about 8.0.In some embodiments, y is about 8.5. In some embodiments, y is about9.0. In some embodiments, y is about 9.5. In some embodiments, y isabout 10.0. In some embodiments, y is about 10.5. In some embodiments, yis about 11.0. In some embodiments, y is about 11.5. In someembodiments, y is about 12.0.

In some embodiments, Z is boron. In some embodiments, Z is beryllium. Insome embodiments, Z is silicon.

In some embodiments, the composite matrix comprises W_(1-x)V_(x)B₄. Insome embodiments, the composite matrix comprises W_(1-x)Cr_(x)B₄. Insome embodiments, the composite matrix comprises W_(1-x)Nb_(x)B₄. Insome embodiments, the composite matrix comprises W_(1-x)Mo_(x)B₄. Insome embodiments, the composite matrix comprises W_(1-x)Ta_(x)B₄. Insome embodiments, the composite matrix comprises W_(1-x)Re_(x)B₄.

Additionally disclosed herein, in certain embodiments, is a method ofproducing a thermodynamically stable tungsten tetraboride compositematrix; the method comprising:

-   -   a) adding into a compression chamber a mixture of boron (B) and        tungsten (W), wherein the ratio of boron to tungsten is between        4 and 11.9 equivalents of boron to 1 equivalent of tungsten;    -   b) compressing the mixture to generate a compressed raw mixture;    -   c) adding the compressed raw mixture to a reaction vessel;    -   d) generating an inert atmosphere within the reaction vessel by        applying a vacuum to the reaction vessel, flushing the reaction        vessel with inert gas, or a combination thereof; and    -   e) heating the reaction vessel to a temperature of between about        1200° C. and about 2200° C. to generate the thermodynamically        stable WB₄ composite matrix.

In some embodiments, the mixture is heated, melted or sintered in anelectrical arc furnace, an induction furnace, or a hot press optionallyequipped with a spark plasma sinter.

In some embodiments, the reaction is a solid state reaction. In someembodiments, the reaction requires the partial melting of at least onecomponent in the mixture. In some embodiments, the reaction requires thecomplete melting of at least one component in the mixture.

In certain embodiments, described herein include methods of making anoxidative resistant composite matrix. In some embodiments, the method ofpreparing an oxidative resistant composite matrix comprises (a) mixingtogether the boron and metals for a time sufficient to produce a powdermixture; (b) pressing the powder mixture under a pressure sufficient togenerate a pellet; and (c) sintering, heating, or melting the pellet ata temperature sufficient to produce a composite matrix.

In some embodiments, the methods described herein, e.g., for generatinga composite matrix of Formula II, a composite matrix of Formula III, acomposite matrix of Formula IV, the thermodynamically stable tungstentetraboride composite matrix, and/or the oxidative resistant compositematrix, require sintering, heating, or melting a mixture of elementsunder an inert atmosphere or vacuum. In some embodiments, the inert orvacuum atmosphere is introduced after transferring the mixture into thereaction vessel and prior to any heating. In some embodiments, a vacuumis applied to the reaction vessel. In some embodiments, the vacuum isapplied for at least 10 minutes, 20 minutes, 30 minutes, or more. Insome embodiments, oxygen is removed from the reaction vessel. In someembodiments, vacuum is applied for a time sufficient to remove at least99% of oxygen from the reaction vessel.

In some embodiments the inert atmosphere is an inert gas such as helium,argon or dinitrogen. In some embodiments, the reaction vessel is purgedwith an inert gas to generate the inert atmosphere. In some embodiments,the reaction vessel is subjected to at least one cycle of applying avacuum and flushing the reaction vessel with an inert gas to removeoxygen from the reaction vessel. In some cases, the reaction vessel issubjected to 2, 3, 4, 5, 6, or more cycles of applying a vacuum andflushing the reaction vessel with an inert gas to remove oxygen from thereaction vessel. In some cases, this process is repeated until desiredoxygen levels persist.

In some embodiments, the mixture is heated until the boron melts anddissolves the other metals, forming a liquid solution. In someembodiments, the liquid boron does not dissolve the metals, and themixture is heated until the boron and metals are melted, e.g., in whichat least 80%, 85%, 90%, 95%, 99%, or 100% of the boron and metals aremelted. In some embodiments, some amount of boron (e.g., less than 10%,5%, 1%, 0.5%, or 0.1% of boron) is volatilized during heating.

In some embodiments, a mixing time is about 5 minutes to about 6 hours.In some embodiments, the mixing time is about 5 minutes, about 10minutes, about 15 minutes, about 20 minutes, about 30 minutes, about 45minutes, about 1 hour, about 1.5 hour, about 2 hours, about 3 hours,about 4 hours, about 5 hours, or about 6 hours. In some embodiments, themixing time is at least 5 minutes or more. In some embodiments, themixing time is about 10 minutes or more. In some embodiments, the mixingtime is about 20 minutes or more. In some embodiments, the mixing timeis about 30 minutes or more. In some embodiments, the mixing time isabout 45 minutes or more. In some embodiments, the mixing time is about1 hour or more. In some embodiments, the mixing time is about 2 hours ormore. In some embodiments, the mixing time is about 3 hours or more. Insome embodiments, the mixing time is about 4 hours or more. In someembodiments, the mixing time is about 5 hours or more. In someembodiments, the mixing time is about 6 hours or more. In someembodiments, the mixing time is about 8 hours or more. In someembodiments, the mixing time is about 10 hours or more. In someembodiments, the mixing time is about 12 hours or more.

In some embodiments, a pressure of up to 36,000 psi is utilized togenerate a pellet. In some embodiments, the pressure is up to 34,000psi. In some embodiments, the pressure is up to 32,000 psi. In someembodiments, the pressure is up to 30,000 psi. In some embodiments, thepressure is up to 28,000 psi. In some embodiments, the pressure is up to26,000 psi. In some embodiments, the pressure is up to 24,000 psi. Insome embodiments, the pressure is up to 22,000 psi. In some embodiments,the pressure is up to 20,000 psi. In some embodiments, the pressure isup to 18,000 psi. In some embodiments, the pressure is up to 16,000 psi.In some embodiments, the pressure is up to 15,000 psi. In someembodiments, the pressure is up to 14,000 psi. In some embodiments, thepressure is up to 10,000 psi. In some embodiments, the pressure is up to8,000 psi. In some embodiments, the pressure is up to 5,000 psi. In someembodiments, the pressure is up to 3,000 psi. In some embodiments, thepressure is up to 2,000 psi. In some embodiments, the pressure is up to1,000 psi.

In some embodiments, the pellets are compressed using a hydraulic press.In some embodiments, the powder is compressed under a 1-20 ton load. Insome embodiments, the powder is compressed under a 2-18 ton load. Insome embodiments, the powder is compressed under a 4-16 ton load. Insome embodiments, the powder is compressed under a 6-14 ton load. Insome embodiments, the powder is compressed under a 8-12 ton load. Insome embodiments, the powder is compressed under a 9-11 ton load.

In some embodiments, the pellets are compressed using a hydraulic press.In some embodiments, the powder is compressed under a 1 ton load. Insome embodiments, the powder is compressed under a 2 ton load. In someembodiments, the powder is compressed under a 3 ton load. In someembodiments, the powder is compressed under a 4 ton load. In someembodiments, the powder is compressed under a 5 ton load. In someembodiments, the powder is compressed under a 6 ton load. In someembodiments, the powder is compressed under a 7 ton load. In someembodiments, the powder is compressed under an 8 ton load. In someembodiments, the powder is compressed under a 9 ton load. In someembodiments, the powder is compressed under a 10 ton load. In someembodiments, the powder is compressed under a 11 ton load. In someembodiments, the powder is compressed under a 12 ton load. In someembodiments, the powder is compressed under a 13 ton load. In someembodiments, the powder is compressed under a 14 ton load. In someembodiments, the powder is compressed under a 15 ton load. In someembodiments, the powder is compressed under a 20 ton load. In someembodiments, the metal and boron are compressed into a form that is nota pellet.

In some embodiments, a method described herein further comprisessintering, heating, or melting a mixture of elements. In someembodiments, the mixture has been blended. In some embodiments, thesintering, heating, or melting generates a composite matrix. In someembodiments, the temperature during sintering, heating, or melting isfrom 1000° C. to 4000° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1100° C. to 3600° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1200° C. to 2200° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1300° C. to 2200° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1400° C. to 2200° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1000° C. to 1800° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1000° C. to 1700° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1200° C. to 1800° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1300° C. to 1700° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1000° C. to 1600° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1500° C. to 1800° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1500° C. to 1700° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1500° C. to 1600° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1600° C. to 2200° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1600° C. to 1900° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1600° C. to 1800° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1600° C. to 1700° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1700° C. to 2200° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1700° C. to 1900° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1700° C. to 1800° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1800° C. to 2000° C. In some embodiments, the temperature duringsintering, heating, or melting is from 1800° C. to 1900° C. In someembodiments, the temperature during sintering, heating, or melting isfrom 1900° C. to 2200° C.

In some embodiments, the temperature for sintering, heating or meltingis about 1000° C., about 1100° C., about 1200° C., about 1300° C., about1400° C., about 1500° C., about 1600° C., about 1700° C., about 1800°C., about 1900° C., about 2000° C., 2100° C., 2200° C., or 2300° C. Insome embodiments, the temperature is about 1000° C. In some embodiments,the temperature is about 1100° C. In some embodiments, the temperatureis about 1200° C. In some embodiments, the temperature is about 1300° C.In some embodiments, the temperature is about 1400° C. In someembodiments, the temperature is about 1500° C. In some embodiments, thetemperature is about 1600° C. In some embodiments, the temperature isabout 1700° C. In some embodiments, the temperature is about 1800° C. Insome embodiments, the temperature is about 1900° C. In some embodiments,the temperature is about 2000° C. In some embodiments, the temperatureis about 2100° C. In some embodiments, the temperature is about 2200° C.In some embodiments, the temperature is about 2300° C.

In some embodiments the mixture is heated for about 5 minutes, 10minutes, 15 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes, 120minutes, 180 minutes, 240 minutes, 300 minutes, 360 minutes, 420minutes, 480 minutes, 540 minutes, or more.

In some embodiments, heating occurs through heating the crucible orheating the composition to a target temperature. In some embodiments,heating the crucible or reaction occurs at a rate of about 1° C. perminute. In some embodiments, heating the crucible or reaction occurs ata rate of about 5° C. per minute. In some embodiments, heating thecrucible or reaction occurs at a rate of about 10° C. per minute. Insome embodiments, heating the crucible or reaction occurs at a rate ofabout 15° C. per minute. In some embodiments, heating the crucible orreaction occurs at a rate of about 20° C. per minute. In someembodiments, heating the crucible or reaction occurs at a rate of about25° C. per minute. In some embodiments, heating the crucible or reactionoccurs at a rate of about 30° C. per minute. In some embodiments,heating the crucible or reaction occurs at a rate of about 35° C. perminute. In some embodiments, heating the crucible or reaction occurs ata rate of about 40° C. per minute. In some embodiments, heating thecrucible or reaction occurs at a rate of about 45° C. per minute. Insome embodiments, heating the crucible or reaction occurs at a rate ofabout 50° C. per minute. In some embodiments, heating the crucible orreaction occurs at a rate of about 55° C. per minute. In someembodiments, heating the crucible or reaction occurs at a rate of about60° C. per minute. In some embodiments, heating the crucible or reactionoccurs at a rate of about 65° C. per minute. In some embodiments,heating the crucible or reaction occurs at a rate of about 70° C. perminute. In some embodiments, heating the crucible or reaction occurs ata rate of about 75° C. per minute. In some embodiments, heating thecrucible or reaction occurs at a rate of about 80° C. per minute. Insome embodiments, heating the crucible or reaction occurs at a rate ofabout 90° C. per minute. In some embodiments, heating the crucible orreaction occurs at a rate of about 100° C. per minute.

In some embodiments, heating the crucible or reaction occurs at a rateof about 1° C. to about 100° C. In some embodiments, heating thecrucible or reaction occurs at a rate of at least about 1° C. In someembodiments, heating the crucible or reaction occurs at a rate of atmost about 100° C. In some embodiments, heating the crucible or reactionoccurs at a rate of about 1° C. to about 5° C., about 1° C. to about 10°C., about 1° C. to about 20° C., about 1° C. to about 30° C., about 1°C. to about 40° C., about 1° C. to about 50° C., about 1° C. to about60° C., about 1° C. to about 70° C., about 1° C. to about 80° C., about1° C. to about 90° C., about 1° C. to about 100° C., about 5° C. toabout 10° C., about 5° C. to about 20° C., about 5° C. to about 30° C.,about 5° C. to about 40° C., about 5° C. to about 50° C., about 5° C. toabout 60° C., about 5° C. to about 70° C., about 5° C. to about 80° C.,about 5° C. to about 90° C., about 5° C. to about 100° C., about 10° C.to about 20° C., about 10° C. to about 30° C., about 10° C. to about 40°C., about 10° C. to about 50° C., about 10° C. to about 60° C., about10° C. to about 70° C., about 10° C. to about 80° C., about 10° C. toabout 90° C., about 10° C. to about 100° C., about 20° C. to about 30°C., about 20° C. to about 40° C., about 20° C. to about 50° C., about20° C. to about 60° C., about 20° C. to about 70° C., about 20° C. toabout 80° C., about 20° C. to about 90° C., about 20° C. to about 100°C., about 30° C. to about 40° C., about 30° C. to about 50° C., about30° C. to about 60° C., about 30° C. to about 70° C., about 30° C. toabout 80° C., about 30° C. to about 90° C., about 30° C. to about 100°C., about 40° C. to about 50° C., about 40° C. to about 60° C., about40° C. to about 70° C., about 40° C. to about 80° C., about 40° C. toabout 90° C., about 40° C. to about 100° C., about 50° C. to about 60°C., about 50° C. to about 70° C., about 50° C. to about 80° C., about50° C. to about 90° C., about 50° C. to about 100° C., about 60° C. toabout 70° C., about 60° C. to about 80° C., about 60° C. to about 90°C., about 60° C. to about 100° C., about 70° C. to about 80° C., about70° C. to about 90° C., about 70° C. to about 100° C., about 80° C. toabout 90° C., about 80° C. to about 100° C., or about 90° C. to about100° C.

In some embodiments, heating occurs through heating the crucible orheating the composition to a target temperature. The reaction orcrucible temperature is then held for a period of time. In someembodiments, the reaction or crucible is held at a target temperaturefor about 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 60minutes, 90 minutes, 120 minutes, 180 minutes, 240 minutes, 300 minutes,360 minutes, 420 minutes, 480 minutes, 540 minutes, or more.

In some embodiments, sintering, heating, or melting is carried out usingan electrical current. In some embodiments, melting is carried out byarc-melting. In some embodiments, arc melting is carried out with acurrent (I) of 50 Amps (A) or more. In some embodiments, arc melting iscarried out with a I of 60 A or more. In some embodiments, arc meltingis carried out with a I of 65 A or more. In some embodiments, arcmelting is carried out with a I of 70 A or more. In some embodiments,arc melting is carried out with a I of 75 A or more. In someembodiments, arc melting is carried out with a I of 80 A or more. Insome embodiments, arc melting is carried out with a I of 90 A or more.In some embodiments, arc melting is carried out with a I of 100 A ormore.

In some embodiments, the arc furnace electrode is made of graphite ortungsten metal. In some embodiments, the reaction vessel is watercooled.

In some embodiments, arc melting is performed in an inert gasatmosphere. In some embodiments, arc melting is performed in an argonatmosphere. In some embodiments, arc melting is performed in a heliumatmosphere. In some embodiments, arc melting is performed in adinitrogen atmosphere.

In some embodiments, arc melting is performed for 0.01-10 mins. In someembodiments, arc melting is performed for 0.01-8 mins. In someembodiments, arc melting is performed for 0.01-6 mins. In someembodiments, arc melting is performed for 0.01-5 mins. In someembodiments, arc melting is performed for 0.01-4 mins. In someembodiments, arc melting is performed for 0.5-3 mins. In someembodiments, arc melting is performed for 0.8-2.5 mins. In someembodiments, arc melting is performed for 1-2 mins.

In some embodiments, arc melting is performed until the mixture hasbecome melted. The melting of the mixture may be observed by visually,or by changes in mixtures properties, for example changes in resistance,heat capacity, heat flow, or temperature. In some embodiments, arcmelting is performed until the mixture has become partially melted. Insome embodiments, arc melting is performed until the mixture has becomemostly melted. In some embodiments, arc melting is performed until themixture has become completely melted. In some embodiments, arc meltingis performed until the mixture has become at least 50%, 60%, 70%, 80%,85%, 90%, 95%, or 99% melted. In some embodiments, arc melting isperformed until the mixture has become about 50%, 60%, 70%, 80%, 85%,90%, 95%, or 99% melted.

In some embodiments, sintering is carried out at room temperature. Insome cases, sintering is carried out at a temperature range of betweenabout 23° C. and about 27° C. In some cases, sintering is carried out ata temperature of about 24° C., about 25° C., or about 26° C.

In some embodiments, a sintering, heating, or melting described hereininvolves an elevated temperature and an elevated pressure, e.g., hotpressing. Hot pressing is a process involving a simultaneous applicationof pressure and high temperature, which can accelerate the rate ofdensification of a material (e.g., a composite matrix described herein).In some embodiments, a temperature from 1000° C. to 2200° C. and apressure of up to 36,000 psi are used during hot pressing. In someembodiments, heating is achieved by plasma spark sintering.

In other embodiments, a sintering step described herein involves anelevated pressure and room temperature, e.g., cold pressing. In suchembodiments, pressure of up to 36,000 psi is used.

In some embodiment, a sintering, heating, or melting described herein iscarried out in a furnace. In some embodiments the furnace is aninduction furnace. In some embodiments, the induction furnace is heatedby electromagnetic induction. In some embodiments, the electromagneticradiation used for electromagnetic induction has the frequency andwavelength of radio waves. In some embodiments, the electromagneticradiation used for electromagnetic induction has the frequency fromabout 3 Hz to about 300 GHz and a wavelength from 1 mm to 10,000 km. Insome embodiments, the frequency is from about 3 Hz to about 30 Hz. Insome embodiments, the frequency is from about 30 Hz to about 300 Hz. Insome embodiments, the frequency is from about 300 Hz to about 3000 Hz.In some embodiments, the frequency is from about 3 kHz to about 30 kHz.In some embodiments, the frequency is from about 30 kHz to about 300kHz. In some embodiments, the frequency is from about 300 kHz to about3000 kHz. In some embodiments, the frequency is from about 3 MHz toabout 30 MHz. In some embodiments, the frequency is from about 30 MHz toabout 300 MHz. In some embodiments, the frequency is from about 300 MHzto about 3000 MHz. In some embodiments, the frequency is from about 3GHz to about 30 GHz. In some embodiments, the frequency is from about 30GHz to about 300 GHz.

In some embodiments, the reaction vessel is lined with carbon graphitewhich is inductively heated by electromagnetic radiation with afrequency of 10-50 kHz. In some embodiments, the frequency is from about50 Hz to about 400 kHz. In some embodiments, the frequency is from about60 Hz to about 400 kHz. In some embodiments, the frequency is from about100 Hz to about 400 kHz. In some embodiments, the frequency is fromabout 1 kHz to about 400 kHz. In some embodiments, the frequency is fromabout 10 kHz to about 300 kHz.

In some embodiments, the frequency is from about 50 kHz to about 200kHz. In some embodiments, the frequency is from about 100 kHz to about200 kHz. In some embodiments, the frequency is from about 1 kHz to about50 kHz. In some embodiments, the frequency is from about 50 kHz to about100 kHz.

In some embodiments, heating or melting described herein is carried outin a conventional furnace. In some embodiments, a conventional furnaceheats the crucible or sample through the use of metal coils orcombustion.

In some embodiments, the raw mixtures react with oxygen and carbon uponheating. Heating the mixture by electrical arc furnace, inductionfurnace, conventional furnace, hot pressing or plasma sintering requiresthat the majority of the raw mixture not come in contact with oxygen orcarbon. In some embodiments, the reaction mixture (compressed orotherwise) is optionally shielded from the reaction chamber by aninsulating material. In some embodiments, the reaction mixture isoptionally shielded from the reaction chamber by an electricallyinsulating material. In some embodiments, at most about 95%, 90%, 85%,80%, 70%, 60%, 50%, 40%, 30%, or less of the surface of the mixture isoptionally shielded from the reaction chamber by the electricallyinsulating material. In some embodiments, the insulating materialcomprises hexagonal boron nitride (h-BN). In some embodiments, theinsulating material does not contain carbon. In some embodiments, thecompressed raw mixture is shielded from the arc furnace electrode by theelectrically insulating material, optionally comprising hexagonal boronnitride.

In some embodiments, the reaction chamber is separated from the reactionmixture by a liner. In some embodiments, the liner is an h-BN liner. Insome embodiments, the liner is a metal liner. In some embodiments, theliner is comprised of one or more transition elements. In someembodiments, the metal liner comprises a group 4, group 5, group 6, orgroup 7 transition metal. In some embodiments, the metal liner comprisesat least one of the following elements: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,W, Mn, Tc, and Re. In some embodiments, the metal liner comprises Nb,Ta, Mo, or W. In some embodiments, the metal liner comprises Nb. In someembodiments, the metal liner comprises Ta. In some embodiments, themetal liner comprises Mo. In some embodiments, the metal liner comprisesW.

In some embodiments, the liner has a thickness of about 0.05 mm. In someembodiments, the liner has a thickness of about 0.10 mm. In someembodiments, the liner has a thickness of about 0.15 mm. In someembodiments, the liner has a thickness of about 0.20 mm. In someembodiments, the liner has a thickness of about 0.25 mm. In someembodiments, the liner has a thickness of about 0.30 mm. In someembodiments, the liner has a thickness of about 0.05 mm. In someembodiments, the liner has a thickness of about 0.35 mm. In someembodiments, the liner has a thickness of about 0.40 mm. In someembodiments, the liner has a thickness of about 0.05 mm. In someembodiments, the liner has a thickness of about 0.45 mm. In someembodiments, the liner has a thickness of about 0.50 mm. In someembodiments, the liner has a thickness of about 0.75 mm. In someembodiments, the liner has a thickness of about 1.0 mm. In someembodiments, the liner has a thickness of about 5.0 mm. In someembodiments, the liner has a thickness of about 10.0 mm.

In some embodiments, the liner has a thickness of greater than or about0.05 mm. In some embodiments, the liner has a thickness of greater thanor about 0.10 mm. In some embodiments, the liner has a thickness ofgreater than or about 0.15 mm. In some embodiments, the liner has athickness of greater than or about 0.20 mm. In some embodiments, theliner has a thickness of greater than or about 0.25 mm. In someembodiments, the liner has a thickness of greater than or about 0.30 mm.In some embodiments, the liner has a thickness of greater than or about0.05 mm. In some embodiments, the liner has a thickness of greater thanor about 0.35 mm. In some embodiments, the liner has a thickness ofgreater than or about 0.40 mm. In some embodiments, the liner has athickness of greater than or about 0.05 mm. In some embodiments, theliner has a thickness of greater than or about 0.45 mm. In someembodiments, the liner has a thickness of greater than or about 0.50 mm.In some embodiments, the liner has a thickness of greater than or about0.75 mm. In some embodiments, the liner has a thickness of greater thanor about 1.0 mm. In some embodiments, the liner has a thickness ofgreater than or about 5.0 mm. In some embodiments, the liner has athickness of greater than or about 10.0 mm.

In some embodiments, the mixture is completely melted by arc melting,induction furnace, or conventional furnace and allowed to cool. The rateof cooling contributes to the size of the crystallites that form withinthe composite matrix. In some embodiments, the composite matrix iscomposed of crystallites that are less than 10,000 micrometer in size.In some embodiments, the composite matrix is composed of crystallitesthat are less than 1000 micrometer in size. In some embodiments, thecomposite matrix is composed of crystallites that are less than 500micrometer in size. In some embodiments, the composite matrix iscomposed of crystallites that are less than 400 micrometer in size. Insome embodiments, the composite matrix is composed of crystallites thatare less than 300 micrometer in size. In some embodiments, the compositematrix is composed of crystallites that are less than 200 micrometer insize. In some embodiments, the composite matrix is composed ofcrystallites that are less than 100 micrometer in size. In someembodiments, the composite matrix is composed of crystallites that areless than 75 micrometer in size. In some embodiments, the compositematrix is composed of crystallites that are less than 50 micrometer insize. In some embodiments, the composite matrix is composed ofcrystallites that are less than 25 micrometer in size. In someembodiments, the composite matrix is composed of crystallites that areless than 20 micrometer in size. In some embodiments, the compositematrix is composed of crystallites that are less than 10 micrometer insize. In some embodiments, the composite matrix is composed ofcrystallites that are less than 5 micrometer in size. In someembodiments, the composite matrix is composed of crystallites that areless than 4 micrometer in size. In some embodiments, the compositematrix is composed of crystallites that are less than 3 micrometer insize. In some embodiments, the composite matrix is composed ofcrystallites that are less than 2 micrometer in size. In someembodiments, the composite matrix is composed of crystallites that areless than 1 micrometer in size.

In some embodiments, the reaction vessel is water cooled. In someembodiments, the reaction vessel is graphite lined.

In some embodiments, the composite matrix is crystalline. In someembodiments, the composite matrix exhibits an X-ray powder diffractionpattern containing one or more peaks found in the X-ray powderdiffraction pattern of WB₄ seen in Table 3. In some embodiments, thecomposite matrix exhibits at least one X-ray powder diffraction patternpeak at about 24.2. In some embodiments, the composite matrix exhibitsat least one X-ray powder diffraction pattern peak at about 34.5. Insome embodiments, the composite matrix exhibits at least one X-raypowder diffraction pattern peak at about 45.1. In some embodiments, thecomposite matrix exhibits at least one X-ray powder diffraction patternpeak at about 47.5. In some embodiments, the composite matrix exhibitsat least one X-ray powder diffraction pattern peak at about 61.8. Insome embodiments, the composite matrix exhibits at least one X-raypowder diffraction pattern peak at about 69.2. In some embodiments, thecomposite matrix exhibits at least one X-ray powder diffraction patternpeak at about 69.4. In some embodiments, the composite matrix exhibitsat least one X-ray powder diffraction pattern peak at about 79.7. Insome embodiments, the composite matrix exhibits at least one X-raypowder diffraction pattern peak at about 89.9. In some embodiments, thecomposite matrix exhibits at least one X-ray powder diffraction patternpeak at about 110.2. In some embodiments, the composite matrix exhibitsat least one X-ray powder diffraction pattern peak at about 34.5 orabout 45.1. In some embodiments, the composite matrix exhibits at leastone X-ray powder diffraction pattern peak at about 47.5, about 61.8,about 69.2, about 69.4, about 79.7, about 89.9, about or about 110.2. Insome embodiments, the composite matrix exhibits at least one X-raypowder diffraction pattern peak at about 24.2, about 28.1, about 34.5,about 42.5, about 45.1, about 47.5, about 55.9, about 61.8, about 69.2,about 69.4±0.2, 79.7, about 89.9, or about 110.2. In some embodiments,the composite matrix exhibits at least two X-ray powder diffractionpattern peaks at about 24.2, about 28.1, about 34.5, about 42.5, about45.1, about 47.5, about 55.9, about 61.8, about 69.2, about 69.4±0.2,79.7, about 89.9, or about 110.2. In some embodiments, the compositematrix exhibits at least three X-ray powder diffraction pattern peaks atabout 24.2, about 28.1, about 34.5, about 42.5, about 45.1, about 47.5,about 55.9, about 61.8, about 69.2, about 69.4±0.2, 79.7, about 89.9, orabout 110.2. In some embodiments, the composite matrix exhibits at leastfour X-ray powder diffraction pattern peaks at about 24.2, about 28.1,about 34.5, about 42.5, about 45.1, about 47.5, about 55.9, about 61.8,about 69.2, about 69.4±0.2, 79.7, about 89.9, or about 110.2. In someembodiments, the composite matrix exhibits at least five X-ray powderdiffraction pattern peaks at about 24.2, about 28.1, about 34.5, about42.5, about 45.1, about 47.5, about 55.9, about 61.8, about 69.2, about69.4±0.2, 79.7, about 89.9, or about 110.2. In some embodiments, thecomposite matrix exhibits at least six X-ray powder diffraction patternpeaks at about 24.2, about 28.1, about 34.5, about 42.5, about 45.1,about 47.5, about 55.9, about 61.8, about 69.2, about 69.4±0.2, 79.7,about 89.9, or about 110.2.

Tools and Abrasive Materials

Wear and tear are part of the normal use of tools and machines. Thereare different types of wear mechanisms, including, for example, abrasionwear, adhesion wear, attrition wear, diffusion wear, fatigue wear, edgechipping (or premature wear), and oxidation wear (or corrosive wear).Abrasion wear occurs when the hard particle or debris, such as chips,passes over or abrades the surface of a cutting tool. Adhesion wear orattrition wear occurs when debris removes microscopic fragments from atool. Diffusion wear occurs when atoms in a crystal lattice move from aregion of high concentration to a region of low concentration and themove weakens the surface structure of a tool. Fatigue wear occurs at amicroscopic level when two surfaces slide in contact with each otherunder high pressure, generating surface cracks. Edge chipping orpremature wear occurs as small breaking away of materials from thesurface of a tool. Oxidation wear or corrosive wear occurs as a resultof a chemical reaction between the surface of a tool and oxygen.

In some embodiments, a composite matrix described herein (e.g., acomposite matrix of Formula I, a composite matrix of Formula II, acomposite matrix of Formula III, and/or a composite matrix of FormulaIV) is used to make, modify, or coat a tool or an abrasive material. Insome embodiments, a composite matrix described herein (e.g., a compositematrix of Formula I, a composite matrix of Formula II, a compositematrix of Formula III, and/or a composite matrix of Formula IV) iscoated onto the surface of a tool or an abrasive material. In someembodiments, the surface of a tool or an abrasive material is modifiedwith a composite matrix described herein (e.g., a composite matrix ofFormula I, a composite matrix of Formula II, a composite matrix ofFormula III, and/or a composite matrix of Formula IV). In someembodiments, the surface of a tool or abrasive material comprises acomposite matrix described herein (e.g., a composite matrix of FormulaI, a composite matrix of Formula II, a composite matrix of Formula III,and/or a composite matrix of Formula IV).

In some embodiments, a tool or abrasive material comprises a cuttingtool. In some embodiments, a tool or abrasive material comprises a toolor a component of a tool for cutting, drilling, etching, engraving,grinding, carving, or polishing. In some embodiments, a tool or abrasivematerial comprises a metal bond abrasive tool, for example, such as ametal bond abrasive wheel or grinding wheel. In some embodiments, a toolor abrasive material comprises drilling tools. In some embodiments, atool or abrasive material comprises drill bits, inserts or dies. In someembodiments, a tool or abrasive material comprises tools or componentsused in downhole tooling. In some embodiments, a tool or abrasivematerial comprises an etching tool. In some embodiments, a tool orabrasive material comprises an engraving tool. In some embodiments, atool or abrasive material comprises a grinding tool. In someembodiments, a tool or abrasive material comprises a carving tool. Insome embodiments, a tool or abrasive material comprises a polishingtool.

Certain Terminologies

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which the claimed subject matter belongs. It is to be understoodthat the detailed description are exemplary and explanatory only and arenot restrictive of any subject matter claimed. In this application, theuse of the singular includes the plural unless specifically statedotherwise. It must be noted that, as used in the specification, thesingular forms “a,” “an” and “the” include plural referents unless thecontext clearly dictates otherwise. In this application, the use of “or”means “and/or” unless stated otherwise. Furthermore, use of the term“including” as well as other forms, such as “include”, “includes,” and“included,” is not limiting.

Although various features of the disclosure may be described in thecontext of a single embodiment, the features may also be providedseparately or in any suitable combination. Conversely, although thedisclosure may be described herein in the context of separateembodiments for clarity, the disclosure may also be implemented in asingle embodiment.

Reference in the specification to “some embodiments”, “an embodiment”,“one embodiment” “another embodiment” or “other embodiments” means thata particular feature, structure, or characteristic described inconnection with the embodiments is included in at least someembodiments, but not necessarily all embodiments, of the disclosure.

As used herein, ranges and amounts can be expressed as “about” aparticular value or range. About also includes the exact amount. Hence“about 5 GPa” means “about 5 GPa” and also “5 GPa.” Generally, the term“about” includes an amount that would be expected to be withinexperimental error, e.g., ±5%, ±10% or ±15%. In some embodiments,“about” includes ±5%. In some embodiments, “about” includes ±10%. Insome embodiments, “about” includes ±15%. In some embodiments, whenrefereeing to X-ray powder diffraction peaks at 2 theta, the term“about” includes ±0.2 Angstroms.

The term “partially” is meant to describe an amount that is less that isless than 95%.

The term “completely” is meant to describe an amount that is equal to ormore than 95%.

The term “thermodynamically stable” or “stable” describes a state ofmatter that that is in chemical equilibrium with its environment at 23°C. and at 1 atmosphere of pressure. Stable states described herein donot consume or release energy at 23° C. and 1 atm.

The term “composite matrix” and “composite” can be used interchangeably,and refers to a collection of atoms wherein at least one component iscrystalline W_(1-x)M_(x)B₄ with variables M and x described above. Theat least one component of crystalline W_(1-x)M_(x)B₄ exhibits X-raypowder diffraction peaks as disclosed herein. In some embodiments, thecomposite matrix comprises crystalline W_(1-x)M_(x)B₄. In someembodiments, the composite matrix consists essentially of crystallineW_(1-x)M_(x)B₄.

The section headings used herein are for organizational purposes onlyand are not to be construed as limiting the subject matter described.

EXAMPLES

These examples are provided for illustrative purposes only and not tolimit the scope of the claims provided herein.

Example 1. X-Ray Diffraction

Powder XRD was carried out on a Bruker D8 Discover Powder X-rayDiffractometer (Bruker Corporation, Germany) utilizing Cu_(Kα) X-rayradiation (λ=1.5418 Å). The following scan parameters were used: 5-100°2θ range, time per step of 0.3 sec, step size of 0.0353° with a scanspeed of 0.1055°/sec. In order to determine the phases present in thepowder X-ray diffraction data, the Joint Committee on Powder DiffractionStandards (JCPDS) database was utilized. The composition and purity ofthe samples were determined on an FEI Nova 230 high resolution scanningelectron microscope (FEI Company, U.S.A.) with an UltraDry EDS detector(Thermo Scientific, U.S.A.). Rietveld refinement utilizing Maud softwarewas carried out to determine the cell parameters.

Table 1 shows unit cell data, density and % phase for WB₄ prepared withvariable boron to metal ratios by arc-melting. The density of “pure” WB₄is between 8.5-9.5 g/cm3, which would not account for the excess boronwhich precipitates at the grain boundaries. In the case of “real world”samples, with an excess of boron, such that the formulation is W:B, 1:10(up to 1:12), samples will have a density of 5.15 g/cm3. The densitydecreases as the boron content increases due to the presence ofcrystalline boron at grain boundaries. Boron has a density of 2.29g/cm3, therefore the weighted average is shifted to a lower overalldensity.

The crystal structure of tungsten tetraboride (P6₃/mmc) is shown in FIG.1 . Tungsten atoms are shown in black, while boron atoms are shown inhalf grey; half-filled atoms to depict partial occupancy. X-ray powderdiffractograms of WB₄ prepared by arc melting with a variable boroncomposition FIG. 2 . Tungsten tetraboride forms at all ratios of W:B;tungsten diboride, WB₂ appears below W:B ratio of 1:9.0.

TABLE 1 % WB₂ + W:B a (Å) c (Å) ρ (g/cm³) % β-B WB₄  1:11.6 5.202(1)6.341(1) 5.15^(d) 44.42 55.78  1:11.0 5.201(3) 6.338(1) 5.38 — —  1:10.55.202(3) 6.338(3) 5.44 48.28 51.72  1:10.0 5.203(5) 6.340(2) 5.69 — —1:9.5 5.201(1) 6.337(3) 5.73 43.15 56.85 1:9.0 5.201(2) 6.336(2) 6.1242.95 57.05 1:8.5 5.201(4) 6.337(2) 6.29 36.18 63.82 1:8.0 5.203(4)6.338(4) 6.82 34.89 65.11 1:7.0 5.200(2) 6.335(1) 7.51 32.81 67.19 1:6.05.202(1) 6.338(1) 7.94 30.53 69.47 1:4.5 5.200(1) 6.336(2) 8.46 21.5078.50The standard deviations are given in brackets; % phase values calculatedfrom area analysis of SEM images; density of tungsten tetraboride phasefrom XRD is 8.40 g/cm³.

Density (ρ) measurements were performed utilizing a densitydetermination kit (Mettler-Toledo, U.S.A.) by measuring the weights ofthe samples in air and in an auxiliary liquid (ethanol); the density wascalculated using the following formula:

$\rho = {{\frac{A}{A - B}( {\rho_{0} - \rho_{L}} )} + \rho_{L}}$where A is the weight of the sample in air, B is the weight of thesample in the auxiliary liquid (ethanol), ρ₀ is the density of auxiliaryliquid (ethanol—0.789 g/cm³), and ρ_(L) is the density of air (0.0012g/cm³).

These data show that the tungsten tetraboride phase, is present at alltungsten to boron ratios. Moreover, WB₄ without any secondarytungsten-boron phases can be readily prepared with a W:B ratio of 1:11.6to 1:9.0; however, due to the stoichiometry used, excess crystallineboron (β-rhombohedral boron) will be present in the samples. A lowerboride phase, tungsten diboride appears at W:B ratios of less than orequal to 1:11.6, as seen from the phase diagram; from the pXRD, thediboride peaks show at W:B ratios at 1:8.5 and lower. Analyzing thephase diagram for the tungsten-boron system, it should be noted thatsince tungsten tetraboride is an incongruently melting phase and aperitectic decomposition product, it can coexist with excess boron uponcooling a melt of nominal composition W:B of 1:4. Table 1 provides theunit cell data for WB₄, which indicates that for boron ratios of 11.6down to 4.5 there are no significant changes in the lattice parametersfor the tungsten tetraboride phase.

Table 2 shows unit cell data for W_(1-x)Ta_(x)B₄ prepared by arc meltingand with a boron to metal ratio of 4.5 to 1. X-ray powder diffractogramsof W_(1-x)Ta_(x)B₄ shown in FIG. 2 . Tungsten tetraboride, forms at allconcentrations of Ta; tungsten diboride, WB₂ disappears at a tantalumcontent of 25 at. % Ta, visible TaB₂ peaks appear at a tantalum contentof 50 at. % Ta. The sample with a composition of W_(0.668)Ta_(0.332)B₄contains only WB₄ peaks.

TABLE 2 Alloy at. % Ta a (Å) c (Å) WB₄ 0.0 5.200(1) 6.336(2)W_(0.917)Ta_(0.083)B₄ 8.3 5.209(2) 6.353(3) W_(0.834)Ta_(0.166)B₄ 16.65.216(3) 6.365(2) W_(0.750)Ta_(0.250)B₄ 25.0 5.217(2) 6.365(4)W_(0.668)Ta_(0.332)B₄ 33.2 5.224(3) 6.377(4) W_(0.585)Ta_(0.415)B₄ 41.55.232(2) 6.398(3) W_(0.500)Ta_(0.500)B₄ 50.0 5.242(1) 6.417(2)The standard deviations are given in brackets.

Table 3 shows X-ray powder diffraction data collected from thecrystalline WB₄ synthesized by the methods disclosed herein. Table 3contains the location of each diffraction peak in terms of Millerindices (h,k,l), distance (Angstroms), and 2 theta (degrees). Table 3also contains the relative intensity of each diffraction peak ascompared to the diffraction peak located at 2 theta=24.232. Thediffraction data was collected at 293 K with an X-ray diffractometerutilizing a Copper radiation source (λ=1.5418 Å).

TABLE 3 No. h k l d[A] 2 Theta[deg] I[%] 1 1 0 0 4.51000 19.668 4.0 2 10 1 3.67000 24.232 100.0 3 0 0 2 3.17000 28.127 30.0 4 1 1 0 2.5980034.495 65.0 5 2 0 0 2.25000 40.041 2.0 6 2 0 1 2.12500 42.507 25.0 7 1 12 2.01000 45.068 80.0 8 1 0 3 1.91100 47.543 20.0 9 2 0 2 1.83600 49.6132.0 10 2 1 0 1.70000 53.888 2.0 11 2 1 1 1.64400 55.881 25.0 12 0 0 41.58400 58.195 10.0 13 2 0 3 1.54000 60.026 10.0 14 3 0 0 1.50100 61.75320.0 15 3 0 2 1.35600 69.231 20.0 16 1 1 4 1.35300 69.407 20.0 17 2 1 31.32500 71.092 10.0 18 2 2 0 1.30000 72.675 8.0 19 3 1 1 1.22500 77.92610.0 20 1 0 5 1.22000 78.306 4.0 21 2 2 2 1.20200 79.710 20.0 22 2 1 41.16100 83.132 2.0 23 4 0 0 1.12500 86.426 2.0 24 4 0 1 1.10900 87.9894.0 25 2 0 5 1.10500 88.390 4.0 26 3 0 4 1.09000 89.934 20.0 27 3 1 31.07500 91.542 6.0 28 4 0 2 1.06100 93.106 2.0 29 0 0 6 1.05700 93.5652.0 30 3 2 0 1.03400 96.313 2.0 31 3 2 1 1.02000 98.085 6.0 32 2 1 51.01700 98.475 6.0 33 2 2 4 1.00300 100.349 6.0 34 4 0 3 0.99300 101.7432.0 35 4 1 0 0.98300 103.187 8.0 36 1 1 6 0.97900 103.779 10.0 37 2 0 60.95600 107.366 2.0 38 4 1 2 0.93900 110.238 16.0 39 3 2 3 0.92800112.211 6.0Data collected at ambient temperature (293 K), radiation source Cu_(Kα)(λ=1.5418 Å)

FIG. 3 shows X-ray powder diffractograms of W_(1-x)Ta_(x)B₄ prepared byarc melting and with a boron to metal ratio of 4.5 to 1.

FIG. 4 shows X-ray powder diffractograms of W_(1-x)Nb_(x)B₄ prepared byarc melting and wih a boron to metal ratio of 4.5 to 1. Tungstentetraboride forms at all concentrations of Nb. Tungsten diboride, WB₂disappears at a niobium content of 33.2 at. % Nb, visible NbB₂ peaksappear at a niobium content of 33.2 at. % Nb.

FIG. 5 shows X-ray powder diffractograms of W_(1-x)V_(x)B₄ prepared byarc melting and wih a boron to metal ratio of 4.5 to 1. Tungstentetraboride forms at all concentrations of V. Visible VB₂ peaks appearat a vanadium content of 33.3 at. % V.

FIG. 6 shows X-ray powder diffractograms of W_(1-x)Mo_(x)B₄ prepared byarc melting and wih a boron to metal ratio of 4.5 to 1. Powder XRDpatterns (15-80° 2Θ) of alloys of W_(1-x)Mo_(x)B₄, prepared with a M:Bratio of 1:4.5. Tungsten tetraboride forms at all concentrations of Mo,as molybdenum also forms a tetraboride with a similar crystal structure,MoB₄. Tungsten diboride, WB₂ is present at all concentrations of Mo;MoB₂ forms at ˜50 at. % Mo.

FIG. 7 shows X-ray powder diffractograms of W_(1-x)Re_(x)B₄ prepared byarc melting and wih a boron to metal ratio of 4.5 to 1. Powder XRDpatterns (15-80° 2Θ) of alloys of W_(1-x)Re_(x)B₄ prepared with a M:Bratio of 1:4.5. Tungsten tetraboride, forms at concentrations of Re from0-41.5 at. % Re. Tungsten diboride, WB₂ is present at concentrations ofRe from 0-25.0 at. % Re; ReB₂ forms at all concentrations of Re.

FIG. 8 shows X-ray powder diffractograms of W_(1-x)Cr_(x)B₄ prepared byarc melting and wih a boron to metal ratio of 4.5 to 1. Powder XRDpatterns (15-80° 2Θ) of alloys of W_(1-x)Cr_(x)B₄, prepared with a M:Bratio of 1:4.5. Tungsten tetraboride, forms at concentrations of Cr from0-41.5 at. % Cr. Tungsten diboride, WB₂ is present at concentrations ofRe from 0-41.5 at. % Cr; CrB₂ forms at all concentrations of Cr from25-50 at. % Cr.

Example 2. Thermal Analysis

A Pyris Diamond TGA/DTA unit (TG-DTA, Perkin-Elmer Instruments, U.S.A.)was utilized in order to perform the thermogravimetric analyses, eachwith the following heating profile: heat in air from 25 to 200° C. at arate of 20° C./min, hold at 200° C. for 30 minutes to remove anymoisture, heat from 200 to 1000° C. at a rate of 2° C./min, hold at1000° C. for 2 hours and cool from 1000 to 25° C. at a rate of 5°C./min. XRD analysis was then performed in order to identify theresulting phase(s).

FIG. 9 shows the thermal stability of tungsten tetraboride alloysprepared with a W:B ratio of 1:11.6 and 1:9.0, as measured by thermalgravimetric analysis in air. These data show that both of these alloysare stable to a temperature of ˜455° C., using the extrapolated onsetmethod (˜450° C. for WB₄ with W:B=11.6 and ˜465° C. for W:B=1:9.0).

Example 3. Hardness Determination

Hardness measurements were done on polished samples using a load-celltype multi-Vickers hardness tester (Leco, U.S.A.) with a pyramidaldiamond indenter tip. Under each applied load: 0.49, 0.98, 1.96, 2.94and 4.9 N, 10 indents were made in randomly chosen spots on the samplesurface. The lengths of the diagonals of the indents were measured usinga high-resolution optical microscope, Zeiss Axiotech 100HD (Carl ZeissVision GmbH, Germany) with a 500× magnification. Vickers hardness values(H_(v), in GPa) were calculated using the following formula and thevalues of all 10 indents per load were averaged:

$H_{v} = \frac{1854{{.4}\; F}}{d^{z}}$where d is the arithmetic average length of the diagonals of each indentin microns and F is the applied load in Newtons (N).

Measurements of Vickers microindentation hardness of W_(1-x)Ta_(x)B₄,c-BN, diamond, WB₄ and Re₄ are show in Table 4. Measurements of Vickersmicroindentation hardness of WB₄ prepared with variable boron to metalratios is shown in FIG. 10 . The hardness of WB₄ prepared with a B:Wratio from 9.0-11.6 to 1 have a hardness of about 40 GPa or more at 0.49N.

TABLE 4 Composition Vickers Hardness (GPa) Load (N) c-BN 47^(a) 9.8Diamond 85^(a) 9.8 WB₄   46.2^(b) 0.49 ReB₂ 48^(a) 0.49W_(0.668)Ta_(0.332)B₄   33.7^(c) 0.49

Example 4. Scanning Electron Microscopy and Energy Dispersive X-RayAnalysis (SEM & EDS)

FIG. 11 shows SEM images of WB₄ prepared by arc melting with a variableboron content from 4.5 to 11.6. Black areas correspond to boron, whilegray areas correspond to metallic phases (tungsten tetra- anddiborides). For samples with a W:B of more than 1:8.5, only tungstentetraboride and boron are present; for samples with W:B of less than1:8.5, WB₂ (lighter gray areas) can be seen alongside tungstentetraboride. All images were taken at a magnification of 1000× and thescale bar in the images is 100 μm.

FIG. 12 shows SEM images of surfaces of alloys of WB₄ with a ratio ofW:B=1:4.5. Black areas correspond to boron, while gray areas correspondto metallic phases: tungsten tetraboride (dark gray) and WB₂ (lightgray). The images were taken at a magnification of 1000× (left), 2000×(Middle) and 5000× (right) and the scale bars in the images are 100, 50and 20 respectively. (Bottom) SEM image and EDS maps (boron K line andtungsten L line) for a sample of WB₄ with a ratio of W:B=1:4.5. Blackareas correspond to crystalline β-rhombohedral boron (seen in B map).The W map shows the tungsten “rich” areas corresponding to WB₂ and moretungsten “poor” areas corresponding to tungsten tetraboride. The imageand maps were taken at 2000× magnification; the scale bar in the imagesis 50 μm.

FIG. 13 shows EDS elemental maps for boron (K line), tantalum (L line)and tungsten (L line) for the W_(0.668) Ta_(0.332)B_(4.5) alloy, showingthe presence of both tantalum and tungsten in the metal-boron phase; theboron rich areas are β-rhombohedral boron.

Example 5. Preparation with Electric Arc Furnace

Electric Arc Furnace (EAF, also known as a Plasma Arc Furnace): useselectric current discharge to provide localized, superheated gases tomelt materials. It is advantageous to have electrically conductivematerials in order to facilitate faster melting, but not necessary. Theelectrode is commonly made of graphite (carbon) or tungsten metal. Thereaction vessel is made of metals (such as copper, tungsten, ormolybdenum); both the reaction vessel and the electrode must be watercooled, otherwise they will be consumed in the melting process. In EAFsynthesis, the reaction charge is completely melted. This meltingfacilitates the formation of the tetraboride phase so long as thestoichiometry is above M:B 1:4. If the reaction mixture issub-stoichiometric, it will produce a mixture of WB₂ and WB₄. For EAFfurnaces, the presence of a conductive path necessitates a conductivepoint for the arc to strike. As such, the crucible/cauldron may not beentirely covered with an electrically insulated material such as h-BN.Therefore it is necessary for a portion of the conductivehearth/cauldron to be exposed. In some instances the material may bemelted with or without a h-bn coating, so long as the conductive path isnot prevented.

Alloys of WB₄ with a variable boron content (boron ratio of 11.6, 10.5,10.0, 9.5, 9.0, 8.5, 8.0, 7.0, 6.0 and 4.5 to 1 tungsten), and alloys ofWB₄ with Ta, Nb, V, Mo, Re and Cr were prepared using: tungsten (99.95%,Strem Chemicals, U.S.A.), amorphous boron (99+%, Strem Chemicals,U.S.A.), tantalum (99.9%, Materion, U.S.A.), niobium (99.8%, StremChemicals, U.S.A.), vanadium (99.5%, Strem Chemicals, U.S.A.),molybdenum (99.9%, Strem Chemicals, U.S.A.), rhenium (99.99%, CeracSpecialty Inorganics, now Materion), chromium (99.9%, ResearchOrganics/Inorganics Chemical Corp.). For these alloys of WB₄ the M:Bratio was kept at 1:4.5. For samples of 1-x W:x Ta:4.5 B, 1-x W:x Nb:4.5B, 1-x W:x Mo:4.5 B, 1-x W:x Re:4.5 B and 1-x W:x Cr:4.5 B, x=0.083,0.166, 0.250, 0.332, 0.415 and 0.500. For 1-y W:y V:4.5 B, y=0.166,0.332, 0.500, 0.668 and 0.854.

Metal powders and boron in desired proportions were calculated, weighedand mixed with a pestle in an agate mortar to ensure homogeneity. Themixtures of powders were pressed into pellets under a 10-ton load usinga hydraulic press (Carver). These cold-pressed pellets were then placedinto an arc-melter chamber on top of a water-cooled copper hearth andarc-melted in an argon atmosphere using a current of I=70 amps for t=1-2minutes.

Synthesis of WB₄ by Arc Furnace

A reaction mixture (W to B ratio of 1 to 8.0) was inserted into areaction vessel with a water cooled carbon (or copper) hearth. Parts ofthe hearth were coated with h-BN to prevent interaction between thecarbon and the mixture carbon hearth. Only partial coverage wasmaintained in order to provide a conductive path for electricaltransmittance. No h-BN coating is needed when using a copper hearth. Thereaction vessel was self-contained. The reaction vessel was pulled undervacuum and held for approximately 10 minutes to facilitate the removalof oxygen from the atmosphere, and then back filled to ambient pressurewith high purity argon. During heating, the reaction was a dynamicallypurged with argon, though a dynamic flow of another shield gas, such ashelium, for example, may also be used. A static atmosphere has alsoyielded acceptable results. An electric arc was established between theelectrode and the hearth plate. As the amperage/power was increased, thereaction mixture began to melt and consolidate. Following the melting ofthe mixture, the electric arc was terminated and the composite permittedto cool. Composite crystallite size was on the order of millimeters, butcan be decreased by increasing the cooling rate or decreasing thereaction mass. Reaction masses of 0.5 g yield sub-micron crystallinecomposites.

Example 6. Preparation with Induction Furnace

The induction furnace uses tunable radio-frequency (RF) induction tolocally heat the crucible or the raw material. Boron is an electricalinsulator, so in most circumstances is not susceptible to RF. Tungstenis RF sensitive, and in some cases, larger particle sizes are used inthe raw materials to start the reaction with boron. On an industrialscale, the reaction vessel is water cooled, and graphite lined. The RFsystem is generally tuned to heat the carbon, which through physicalcontact heats the materials for melting. If the reaction charge is notat least 95% and up to 100% melted, only a solid state reaction willtake place. Preventing the direct contact of the reaction charge withthe graphite crucible walls is necessary. Hexagonal Boron Nitride (h-BN)is an exemplary material to be used for physically insulating thereaction charge from the carbon crucible walls. This material isthermally conducting but electrically insulating; and will not influencethe efficacy of the RF coil. Induction heating requires a materialsusceptible to radio-frequency; carbon is traditionally used as acrucible so a liner is necessary.

Synthesis of WB₄ by Induction Furnace

A reaction mixture (W to B ratio of 1 to 8.0) was inserted into a carboncrucible physically insulated with layers/coatings of h-BN or insertedinto a carbon crucible with an inner h-BN crucible. If the reactionmixture is exposed to carbon directly, such as a contaminant in thereaction mixture, or through contact with the reactor walls, thesynthesis of WB₂ will be facilitated. The carbon present is slightlysoluble in the tungsten, thereby competing with boron, and catalyzingthe diboride phase over the metastable tetraboride phase.

The reaction vessel was pulled under vacuum and held for approximately10 minutes to facilitate the removal of oxygen from the atmosphere. Thereaction vessel was back-filled with high purity argon to ambientpressure and heating commenced. The atmosphere was static. The ramp rateof the heating was targeted as 20° C. per minute to a temperature of1700° C. This temperature was held for 180 minutes. After the hold, thepower supply was shutdown and the reaction vessel allowed to cool. Thereaction product was WB₄ with minimal to non-detectable levels of WB₂present. The product yielded micron-size crystallites (≤50 μm) of WB₄.

Example 7. Preparation with Hot Press with Spark Plasma Sintering

Hot pressing is a high-pressure, low strain process for forming powdercompacts at a high enough temperature to induce sintering. A h-BN linedmold is used to separate the reaction mixture from any reactivematerials. A graphite mold is used when spark plasma sintering isemployed to allow for electrical conductivity and thermal heating athigh pressures. The reaction mixture is insulated from the graphitelining during the reaction to minimize or decrease side productformation relative to an equivalent reaction without insulating thereaction mixture. Spark plasma sintering utilizes directed pulse DCcurrents to sinter the compacted reaction mixtures.

Synthesis of WB₄ by Hot Press

A reaction mixture (W to B ratio of 1 to 8.0) was loaded into anon-carbon container which was then inserted into a graphite containingreaction vessel, which provided a thermally and electrically conductivepathway. It was essential to avoid immediate contact of the reactionmixture with carbon. The reaction vessel is a contained environment withvacuum and/or inert gas atmosphere present. The reaction vessel waspulled under vacuum and held for approximately 10 minutes to facilitatethe removal of oxygen from the atmosphere. The reaction vessel wasback-filled with high purity argon to ambient pressure and heatingcommenced. The synthesis may also be carried out under vacuum. Amechanical or hydraulic pressure ranging from a minimum of 0.5 MPa up to50 MPa or more was applied and maintained throughout the synthesisprocess. The ramp rate of the heating was targeted as 50° C. per minuteto a temperature of 1400° C. This temperature was held for 60 minutes.After the hold at temperature, the power supply was shutdown and thereaction vessel allowed to cool to ambient temperature. The reactionproduct was WB₄ with minimal to non-detectable levels of WB₂ present.

Example 8. Preparation with Conventional Furnace

The conventional furnace uses metal coils to locally heat the crucibleand melt the raw material. On an industrial scale, the reaction vesselis water cooled, and graphite lined. If the reaction charge is not atleast 95% and up to 100% melted, only a solid state reaction will takeplace. Preventing the direct contact of the reaction charge with thegraphite crucible walls is necessary. A Hexagonal Boron Nitride (h-BN),molybdenum, or tungsten liner is an exemplary material to be used forphysically insulating the reaction charge from the carbon cruciblewalls.

Synthesis of WB₄ by Conventional Furnace

A reaction mixture (W to B ratio of 1 to 8.0) was inserted into a carboncrucible fitted with a physically insulating molybdenum, tungsten,niobium, or tantalum liner with a thickness of 0.25 mm. The reactionvessel was pulled under vacuum and held for approximately 10 minutes tofacilitate the removal of oxygen from the atmosphere. The reactionvessel was back-filled with high purity argon to ambient pressure andheating commenced. The atmosphere was static. The ramp rate of theheating was targeted as 20° C. per minute to a temperature of 1700° C.This temperature was held for 180 minutes. After the hold, the reactionvessel allowed to cool. The reaction product was WB₄ with minimal tonon-detectable levels of WB₂ present. The product yielded micron-sizecrystallites (≤50 μm) of WB₄.

EXPERIMENTAL

Alloys of WB₄ with a variable boron content and alloys of WB₄ with Ta,Nb, V, Mo, Re and Cr were prepared using: tungsten (99.95%, StremChemicals, U.S.A.), amorphous boron (99+%, Strem Chemicals, U.S.A.),tantalum (99.9%, Materion, U.S.A.), niobium (99.8%, Strem Chemicals,U.S.A.), vanadium (99.5%, Strem Chemicals, U.S.A.), molybdenum (99.9%,Strem Chemicals, U.S.A.), rhenium (99.99%, Cerac Specialty Inorganics,now Materion), chromium (99.9%, Research Organics/Inorganics ChemicalCorp.).

Metal powders and boron in desired proportions were calculated, weighedand mixed with a pestle in an agate mortar to ensure homogeneity. Themixtures of powders were pressed into pellets under a 10-ton load usinga hydraulic press (Carver). These cold-pressed pellets were then placedinto an arc-melter chamber on top of a water-cooled copper hearth andarc-melted in an argon atmosphere using a current of I=70 amps for t=1-2minutes.

Prepared samples were cut into two halves using a diamond saw (AmeritoolInc., U.S.A.). One half was used for powder X-ray diffraction analysis(PXRD) analysis and crushed into powder (<40 μm) using a Plattner-stylecrusher. The other half was used for scanning electron microscopy(SEM)/energy dispersion spectroscopy (EDS) and Vickers hardness testingand was encapsulated into epoxy using an epoxy/hardener set (Allied HighTech Products Inc., U.S.A.).

To achieve an optically flat surface, the samples were polished usingSiC papers (120-1200 grit sizes, Allied High Tech Products Inc., U.S.A.)and diamond films (30 to 1 micron particle sizes, South Bay TechnologyInc., U.S.A.) on a semi-automated polishing station (South BayTechnology Inc., U.S.A.).

While preferred embodiments of the present disclosure have been shownand described herein, it will be obvious to those skilled in the artthat such embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the disclosure. It should beunderstood that various alternatives to the embodiments of thedisclosure described herein may be employed in practicing thedisclosure. It is intended that the following claims define the scope ofthe disclosure and that methods and structures within the scope of theseclaims and their equivalents be covered thereby.

NUMBERED EMBODIMENTS

The following embodiments recite nonlimiting permutations ofcombinations of features disclosed herein. Other permutations ofcombinations of features are also contemplated. In particular, each ofthese numbered embodiments is contemplated as depending from or relatingto every previous or subsequent numbered embodiment, independent oftheir order as listed. 1. A method of preparing a composite matrixcomprising: combining a sufficient amount of W with an amount of B andoptionally M to generate the composite matrix, wherein the ratio of B toW and M is less than 12 equivalents of B to 1 equivalent of W and M; andthe composite matrix comprises: W_(1-x)M_(x)B₄ wherein: W is tungsten; Bis boron; M is at least one element selected from the group of titanium(Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt(Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb),molybdenum (Mo), ruthenium (Ru), hafnium (Hf), tantalum (Ta), rhenium(Re), yttrium (Y), osmium (Os), iridium (Ir), lithium (Li) and aluminum(Al); and x is from 0 to 0.999. 2. The method of embodiment 1, whereinthe combining comprises i) mixing W, B, and optionally M to generate amixture, ii) transferring the mixture to a reaction vessel, and iii)heating the mixture to a temperature sufficient to induce a reactionbetween W, B, and optionally M to generate the composite matrix. 3. Themethod of embodiment 2, wherein the reaction is a solid state reaction.4. The method of embodiment 2, wherein at least one reaction componentis partially melted. 5. The method of embodiment 2, wherein at least onereaction component is completely melted. 6. The method of embodiment 2,wherein the reaction vessel is further subjected under an inertatmosphere after transferring the mixture to the reaction vessel butprior to heating the mixture. 7. The method of embodiment 6, whereinoxygen is removed from the reaction vessel to generate the inertatmosphere. 8. The method of any one of embodiments 6-7, wherein avacuum is applied to the reaction vessel to generate the inertatmosphere. 9. The method of embodiment 8, wherein the vacuum is appliedfor a time sufficient to remove at least 99% of oxygen from the reactionvessel. 10. The method of embodiment 8 or 9, wherein the vacuum isapplied for at least 10 minutes, 20 minutes, 30 minutes, or more. 11.The method of any one of embodiments 2-10, wherein the reaction vesselis purged with an inert gas to generate the inert atmosphere. 12. Themethod of embodiment 11, wherein the inert gas comprises argon,nitrogen, or helium. 13. The method of any one of embodiments 2-12,wherein the reaction vessel is subjected to at least one cycle ofapplying a vacuum and flushing the reaction vessel with an inert gas toremove oxygen from the reaction vessel. 14. The method of any one ofembodiments 2-13, wherein the mixture is heated to a temperature betweenabout 1200° C. and about 2200° C. 15. The method of embodiment 14,wherein the mixture is heated to a temperature of about 1400° C., 1500°C., 1600° C., 1700° C., 1800° C., 2000° C., 2100° C., or about 2200° C.16. The method of any one of embodiments 2-15, wherein the mixture isheated for about 15 minutes, 90 minutes, 120 minutes, 180 minutes, 240minutes, 360 minutes, or more. 17. The method of any one of embodiments2-16, wherein the mixture is heated by an electric arc furnace. 18. Themethod of embodiment 17, wherein a reaction vessel of the electric arcfurnace is subjected to an inert atmosphere after transferring themixture to the reaction vessel but prior to heating the mixture. 19. Themethod of embodiment 17 or 18, wherein the inert atmosphere is generatedby either applying a vacuum to the reaction vessel, flushing thereaction vessel with an inert gas or any combinations thereof 20. Themethod of any one of embodiments 17-19, wherein the reaction vessel isoptionally coated with an electrically insulating material. 21. Themethod of embodiment 20, wherein at most about 95%, 90%, 85%, 80%, 70%,60%, 50%, 40%, 30%, or less of the surface of the reaction vessel isoptionally coated with the electrically insulating material. 22. Themethod of embodiment 20 or 21, wherein the insulating material compriseshexagonal boron nitride (h-BN). 23. The method of any one of embodiments17-22, wherein the mixture is heated until a liquid solution is formed.24. The method of any one of embodiments 2-16, wherein the mixture isheated by an induction furnace. 25. The method of embodiment 24, whereinthe induction furnace is heated by electromagnetic induction. 26. Themethod of embodiment 25, wherein the electromagnetic radiation used forelectromagnetic induction has the frequency and wavelength of radiowaves. 27. The method of any one of embodiments 2-16, wherein themixture is heated by hot pressing. 28. The method of any one ofembodiments 2-16, wherein the mixture is heated by plasma sparksintering. 29. The method of any one of embodiments 25-28, wherein areaction vessel is subjected to an inert atmosphere after transferringthe mixture to the reaction vessel but prior to heating the mixture. 30.The method of any one of embodiments 25-29, wherein the inert atmosphereis generated by removing oxygen from the reaction vessel in combinationwith either applying a vacuum to the reaction vessel or flushing thereaction vessel with an inert gas. 31. The method of embodiment 30,wherein the inert gas is high purity argon. 32. The method of any one ofembodiments 1-31, wherein M is at least one element selected from thegroup: vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo),tantalum (Ta), and rhenium (Re). 33. The method of any one ofembodiments 1-31, wherein x is 0. 34. The method of embodiment 33,wherein the ratio of B to W is between about 11.9 and about 9equivalents of B to 1 equivalent of W. 35. The method of embodiment 34,wherein the ratio of B to W is about 11.6, about 11, about 10.5, about10, about 9.5, or about 9 equivalents of B to 1 equivalent of W. 36. Themethod of any one of embodiments 1-32, wherein x is from 0.001 to 0.999.37. The method of embodiment 36, wherein x is 0.201-0.400. 38. Themethod of embodiment 36, wherein x is 0.401-0.600. 39. The method ofembodiment 36, wherein x is 0.601-0.800. 40. The method of embodiment36, wherein x is 0.801-0.999. 41. The method of any one of embodiments37-40, wherein the ratio of B to W and M is less than 5 equivalents of Bto 1 equivalent of W and M. 42. The method of embodiment 41, wherein thecomposite matrix comprises W_(1-x)V_(x)B₄. 43. The method of embodiment41, wherein the composite matrix comprises W_(1-x)Cr_(x)B₄. 44. Themethod of embodiment 41, wherein the composite matrix comprisesW_(1-x)Nb_(x)B₄. 45. The method of embodiment 41, wherein the compositematrix comprises W_(1-x)Mo_(x)B₄. 46. The method of embodiment 41,wherein the composite matrix comprises W_(1-x)Ta_(x)B₄. 47. The methodof embodiment 41, wherein the composite matrix comprisesW_(1-x)Re_(x)B₄. 48. The method of embodiment 35, wherein the compositematrix comprises WB₄. 49. The method of embodiment 48, wherein thecomposite matrix is formed with a W to B ratio of 1:11.6. 50. The methodof embodiment 49, wherein the composite matrix has oxidation resistancebelow 450° C. 51. The method of embodiment 48, wherein the compositematrix is formed with a W to B ratio of 1:10.5. 52. The method ofembodiment 48, wherein the composite matrix is formed with a W to Bratio of 1:9.0. 53. The method of embodiment 52, wherein the compositematrix has oxidation resistance below 465° C. 54. The method of any oneof embodiments 1-53, wherein the composite matrix has a density at orabove 4.0 g/cm3. 55. The method of any one of embodiments 1-54, whereinthe method further generates a metal side product. 56. The method ofembodiment 55, wherein the metal side product is tungsten diboride ortungsten monoboride. 57. The method of embodiment 55, wherein the metalside product is less than 10%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or0.01% relative to the percentage of the composite matrix. 58. A methodof producing a thermodynamically stable tungsten tetraboride compositematrix, the method comprising: f) adding into a compression chamber amixture of boron (B) and tungsten (W), wherein the ratio of boron totungsten is between 4 and 11.9 equivalents of boron to 1 equivalent oftungsten; g) compressing the mixture to generate a compressed rawmixture; h) adding the compressed raw mixture to a reaction vessel; i)generating an inert atmosphere within the reaction vessel by applying avacuum to the reaction vessel, flushing the reaction vessel with inertgas, or a combination thereof; and j) heating the reaction vessel to atemperature of between about 1200° C. and about 2200° C. to generate thethermodynamically stable WB₄ composite matrix. 59. The method ofembodiment 58, wherein the compressed raw mixture is heated by anelectric arc furnace. 60. The method of embodiment 59, wherein the arcfurnace electrode comprises graphite or tungsten metal. 61. The methodof embodiment 60, wherein the reaction vessel is optionally coated withan electrically insulating material. 62. The method of embodiment 61,wherein at most about 95%, 90%, 85%, 80%, 70%, 60%, 50%, 40%, 30%, orless of the surface of the reaction vessel is optionally coated with theelectrically insulating material. 63. The method of embodiment 61 or 62,wherein the insulating material comprises hexagonal boron nitride(h-BN). 64. The method of embodiment 61 or 62, wherein the insulatingmaterial does not contain carbon. 65. The method of any one ofembodiments 59-64, wherein the compressed raw mixture is shielded fromthe arc furnace electrode by the electrically insulating material,optionally comprising hexagonal boron nitride. 66. The method of any oneof embodiments 59-65, wherein the composite matrix is composed of gainsor crystallites that are less than 1000 micrometer in size. 67. Themethod of any one of embodiments 59-65, wherein the composite matrix iscomposed of gains or crystallites that are less than 100 micrometer insize. 68. The method of any one of embodiments 59-65, wherein thecomposite matrix is composed of gains or crystallites that are less than50 micrometer in size. 69. The method of any one of embodiments 59-65,wherein the composite matrix is composed of gains or crystallites thatare less than 10 micrometer in size. 70. The method of any one ofembodiments 59-65, wherein the composite matrix is composed of gains orcrystallites that are less than 1 micrometer in size. 71. The method ofembodiment 58, wherein the compressed raw mixture is heated by aninduction furnace. 72. The method of embodiment 71, wherein theinduction furnace is heated by electromagnetic induction. 73. The methodof embodiment 72, wherein the electromagnetic radiation used forelectromagnetic induction has the frequency of radio waves. 74. Themethod of embodiment 58, wherein the mixture is heated by hot pressing.75. The method of embodiment 58, wherein the mixture is heated by plasmaspark sintering. 76. The method of any one of embodiments 71-75, whereinthe reaction vessel is water cooled. 77. The method of any one ofembodiments 71-75, wherein the reaction vessel is graphite lined. 78.The method of embodiment 77, wherein graphite is heated within thereaction vessel. 79. The method of embodiment 78, wherein the compressedraw mixture is shielded from the graphite lined reaction vessel by anelectrically insulating material, optionally comprising hexagonal boronnitride. 80. The method of any one of embodiments 71-79, wherein thecomposite matrix is composed of crystallites that are less than 500micrometers in size. 81. The method of any one of embodiments 71-79,wherein the composite matrix is composed of crystallites that are lessthan 200 micrometers in size. 82. The method of any one of embodiments71-79, wherein the composite matrix is composed of crystallites that areless than 50 micrometers in size. 83. The method of any one ofembodiments 58-82, wherein the density of the composite matrix isbetween about 5.0 g/cm3 and about 7.0 g/cm3. 84. The method ofembodiment 83, wherein the density of the composite matrix is betweenabout 5.1 g/cm3 and about 6.2 g/cm3. 85. The method of any one ofembodiments 58-84, wherein the composite matrix is formed with a W to Bratio of 1:11.6. 86. The method of embodiment 85, wherein the compositematrix has oxidation resistance below 450° C. 87. The method of any oneof embodiments 58-84, wherein the composite matrix is formed with a W toB ratio of 1:10.5. 88. The method of any one of embodiments 58-84,wherein the composite matrix is formed with a W to B ratio of 1:9.0. 89.The method of embodiment 88, wherein the composite matrix has oxidationresistance below 465° C. 90. The method of any one of embodiments 58-89,wherein the composite matrix has a density at or above 4.0 g/cm3. 91. Amethod of producing a composite matrix of Formula (II):W_(1-x)M_(x)B₄(II) wherein: W is tungsten; B is boron; M is at least oneelement selected from the group of titanium (Ti), vanadium (V), chromium(Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium(Ru), hafnium (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium(Os), iridium (Ir), lithium (Li) and aluminum (Al); x is from 0.001 to0.999; and wherein the method comprises: f) adding into a compressionchamber a mixture of boron, tungsten, and M, wherein the ratio of boronto tungsten and M is between 3.5 and 5.0 equivalents of boron to 1equivalent of tungsten and M; g) compressing the mixture to generate acompressed raw mixture; h) adding the compressed raw mixture to areaction vessel; i) generating an inert atmosphere within the reactionvessel by applying a vacuum to the reaction vessel, flushing thereaction vessel with inert gas, or a combination thereof; and j) heatingthe reaction vessel to a temperature of between about 1200° C. and about2200° C. to generate the composite matrix of Formula (II). 92. Themethod of embodiment 91, wherein the compressed raw mixture is heated byan electric arc furnace. 93. The method of embodiment 92, wherein thearc furnace electrode is made of graphite or tungsten metal. 94. Themethod of any one of embodiments 92-93, wherein the compressed rawmixture is partially shielded from the arc furnace electrode by anelectrically insulating material, optionally comprising hexagonal boronnitride. 95. The method of any one of embodiments 92-93, wherein thecomposite matrix is composed of gains or crystallites that are less than100 micrometer in size. 96. The method of any one of embodiments 92-93,wherein the composite matrix is composed of gains or crystallites thatare less than 50 micrometer in size. 97. The method of any one ofembodiments 92-93, wherein the composite matrix is composed of gains orcrystallites that are less than 10 micrometer in size. 98. The method ofany one of embodiments 92-93, wherein the composite matrix is composedof crystallites that are less than 1 micrometer in size. 99. The methodof embodiment 91, wherein the compressed raw mixture is heated by aninduction furnace. 100. The method of embodiment 99, wherein theinduction furnace is heated by electromagnetic induction. 101. Themethod of embodiment 100, wherein the electromagnetic radiation used forelectromagnetic induction has the frequency of radio waves. 102. Themethod of embodiment 91, wherein the mixture is heated by hot pressing.103. The method of embodiment 91, wherein the mixture is heated byplasma spark sintering. 104. The method of any one of embodiments99-103, wherein the reaction vessel is water cooled. 105. The method ofany one of embodiments 99-104, wherein the reaction vessel is graphitelined. 106. The method of embodiment 105, wherein the radiofrequencyinduction is tuned to carbon, and the graphite is heated within thereaction vessel. 107. The method of any one of embodiments 99-106,wherein the compressed raw mixture is shielded from the graphite linedreaction vessel by an electrically insulating material, optionallycomprising hexagonal boron nitride. 108. The method of any one ofembodiments 99-107, wherein the composite matrix is composed of gains orcrystallites that are less than 100 micrometer in size. 109. The methodof any one of embodiments 99-107, wherein the composite matrix iscomposed of gains or crystallites that are less than 50 micrometer insize. 110. The method of any one of embodiments 99-107, wherein thecomposite matrix is composed of gains or crystallites that are less than10 micrometer in size. 111. The method of any one of embodiments 91-110,wherein x is 0.001-0.200. 112. The method of any one of embodiments91-110, wherein x is 0.201-0.400. 113. The method of any one ofembodiments 91-110, wherein x is 0.401-0.600. 114. The method of any oneof embodiments 91-110, wherein x is 0.601-0.800. 115. The method of anyone of embodiments 91-110, wherein x is 0.801-0.999. 116. The method ofany one of embodiments 91-110, wherein M is at least one elementselected from the group: vanadium (V), chromium (Cr), niobium (Nb),molybdenum (Mo), tantalum (Ta), and rhenium (Re). 117. The method ofembodiment 116, wherein the composite matrix comprises W_(1-x)V_(x)B₄.118. The method of embodiment 116, wherein the composite matrixcomprises W_(1-x)Cr_(x)B₄. 119. The method of embodiment 116, whereinthe composite matrix comprises W_(1-x)Nb_(x)B₄. 120. The method ofembodiment 116, wherein the composite matrix comprises W_(1-x)Mo_(x)B₄.121. The method of embodiment 116, wherein the composite matrixcomprises W_(1-x)Ta_(x)B₄. 122. The method of embodiment 116, whereinthe composite matrix comprises W_(1-x)Re_(x)B₄. 123. A method ofproducing a composite material comprising a composite matrix of Formula(III): W_(1-x)M_(x)B₄(III) wherein the percentage of the compositematrix of Formula (III) and boron relative to the composite material isat least 95%, wherein, W is tungsten; B is boron; M is at least oneelement selected from the group of titanium (Ti), vanadium (V), chromium(Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium(Ru), hafnium (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium(Os), iridium (Ir), lithium (Li) and aluminum (Al); x is from 0 to0.999; and wherein the method comprises: h) adding into a compressionchamber a mixture of boron, tungsten, and optionally M, wherein theratio of boron to tungsten and optionally M is less than 12.0equivalents of boron to 1 equivalent of tungsten and optionally M; i)compressing the mixture to generate a compressed raw mixture; j)partially lining the interior of the reaction vessel with an electricinsulator to generate an insulated reaction vessel; k) adding thecompressed raw mixture to the insulated reaction vessel; 1) generatingan inert atmosphere within the reaction vessel by applying a vacuum tothe insulated reaction vessel, flushing the insulated reaction vesselwith inert gas, or a combination thereof; m) arc melting the compressedraw mixture until at least 95% or more of the compressed raw mixture ismelted; and n) cooling the insulated reaction vessel, thereby generatingthe composite material comprising the composite matrix of Formula (III).124. The method of embodiment 123, wherein the composite materialfurther comprises a metal side product, wherein optionally said metalside product is less than 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01%relative to the percentage of the composite matrix. 125. The method ofembodiment 123 or 124, wherein the metal side product is tungstendiboride or tungsten monoboride. 126. The method of any one ofembodiments 123-125, wherein at most about 95%, 90%, 85%, 80%, 70%, 60%,50%, 40%, 30%, or less of the surface of the reaction vessel is coatedwith the electrically insulating material. 127. The method of any one ofembodiments 123-126, wherein the compressed raw mixture is partiallyshielded from the arc furnace electrode by an electrically insulatingmaterial, optionally comprising hexagonal boron nitride. 128. The methodof any one of embodiments 123-127, wherein the insulating materialcomprises hexagonal boron nitride (h-BN). 129. The method of any one ofembodiments 123-128, wherein the compressed raw mixture is melted by anelectric arc furnace or plasma arc furnace. 130. The method ofembodiment 129, wherein the arc furnace electrode is made of graphite ortungsten metal. 131. The method of any of embodiments 123-130, whereinin reaction vessel is water cooled. 132. The method of any one ofembodiments 123-131, wherein the cooling rate of the reaction vessel iscontrolled. 133. The method of any one of embodiments 123-130, whereinthe reaction vessel is allowed to cool to ambient temperature. 134. Themethod of any one of embodiments 123-133, wherein the composite matrixis composed of gains or crystallites that are less than 100 micrometerin size. 135. The method of any one of embodiments 123-133, wherein thecomposite matrix is composed of gains or crystallites that are less than123-133 micrometer in size. 136. The method of any one of embodiments123-133, wherein the composite matrix is composed of gains orcrystallites that are less than 10 micrometer in size. 137. The methodof any one of embodiments 123-133, wherein the composite matrix iscomposed of crystallites that are less than 1 micrometer in size. 138.The method of any one of embodiments 123-137, wherein the reactionvessel is purged with an inert gas to generate the inert atmosphere.139. The method of embodiment 138, wherein the inert gas comprisesargon, nitrogen, or helium. 140. The method of any one of embodiments123-137, wherein the reaction vessel is subjected to at least one cycleof applying a vacuum and flushing the reaction vessel with an inert gasto remove oxygen from the reaction vessel. 141. The method of any one ofembodiments 123-140, wherein x is 0. 142. The method of embodiment 141,wherein the composite matrix comprises WB₄. 143. The method ofembodiment 141 or 142, wherein the ratio of B to W is between about 11.9and about 9 equivalents of B to 1 equivalent of W. 144. The method ofembodiment 143, wherein the ratio of B to W is about 11.6, about 11,about 10.5, about 10, about 9.5, or about 9 equivalents of B to 1equivalent of W. 145. The method of embodiment 144, wherein thecomposite matrix is formed with a W to B ratio of 1:11.6. 146. Themethod of embodiment 145, wherein the composite matrix has oxidationresistance below 450° C. 147. The method of embodiment 144, wherein thecomposite matrix is formed with a W to B ratio of 1:10.5. 148. Themethod of embodiment 144, wherein the composite matrix is formed with aW to B ratio of 1:9.0. 149. The method of embodiment 148, wherein thecomposite matrix has oxidation resistance below 465° C. 150. The methodof any one of embodiments 123-149, wherein the composite matrix has adensity at or above 4.0 g/cm3. 151. The method of any one of embodiments123-140, wherein x is from 0.001 to 0.999. 152. The method of embodiment151, wherein x is 0.201-0.400. 153. The method of embodiment 151,wherein x is 0.401-0.600. 154. The method of embodiment 151, wherein xis 0.601-0.800. 155. The method of embodiment 151, wherein x is0.801-0.999. 156. The method of any one of embodiments 151-155, whereinthe ratio of B to W and M is less than 5 equivalents of B to 1equivalent of W and M. 157. The method of any one of embodiments151-156, wherein M is at least one element selected from the group:vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum(Ta), and rhenium (Re). 158. The method of embodiment 157, wherein thecomposite matrix comprises W_(1-x)V_(x)B₄. 159. The method of embodiment157, wherein the composite matrix comprises W_(1-x)Cr_(x)B₄. 160. Themethod of embodiment 157, wherein the composite matrix comprisesW_(1-x)Nb_(x)B₄. 161. The method of embodiment 157, wherein thecomposite matrix comprises W_(1-x)Mo_(x)B₄. 162. The method ofembodiment 157, wherein the composite matrix comprises W_(1-x)Ta_(x)B₄.163. The method of embodiment 157, wherein the composite matrixcomprises W_(1-x)Re_(x)B₄. 164. A composite matrix comprising a compoundof Formula (I): W_(1-x)M_(x)B₄(I) wherein: W is tungsten; B is boron; Mis at least one element selected from the group: vanadium (V), chromium(Cr), niobium (Nb), molybdenum (Mo), tantalum (Ta), and rhenium (Re);and x is from 0.001 to 0.999. 165. The composite matrix of embodiment144, wherein x is 0.001-0.200. 166. The composite matrix of embodiment144, wherein x is 0.201-0.400. 167. The composite matrix of embodiment144, wherein x is 0.401-0.600. 168. The composite matrix of embodiment144, wherein x is 0.601-0.800. 169. The composite matrix of embodiment144, wherein x is 0.801-0.999. 170. The composite matrix of any one ofembodiments 144-149, wherein the composite matrix is W_(1-x)V_(x)B₄.171. The composite matrix of any one of embodiments 144-149, wherein thecomposite matrix is W_(1-x)Cr_(x)B₄. 172. The composite matrix of anyone of embodiments 144-149, wherein the composite matrix isW_(1-x)Nb_(x)B₄. 173. The composite matrix of any one of embodiments144-149, wherein the composite matrix is W_(1-x)Mo_(x)B₄. 174. Thecomposite matrix of any one of embodiments 144-149, wherein thecomposite matrix is W_(1-x)Ta_(x)B₄. 175. The composite matrix of anyone of embodiments 144-149, wherein the composite matrix isW_(1-x)Re_(x)B₄. 176. A composite matrix produced by the method ofembodiments 1-56, 57-89, 90-121, or 122-162. 177. A tool comprising acomposite matrix produced by the method of embodiments 1-56, 57-89,90-121, or 122-162.

What is claimed is:
 1. A method of preparing a composite matrixcomprising: combining an amount of W with an amount of B and M togenerate the composite matrix, wherein the ratio of B to W and M is lessthan 12 equivalents of B to 1 equivalent of W and M; and the compositematrix comprises:W_(1-X)M_(X)B₄ wherein: W is tungsten; B is boron; M is at least oneelement selected from the group of titanium (Ti), vanadium (V), chromium(Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium(Ru), hafnium (Hf), tantalum (Ta), rhenium (Re), yttrium (Y), osmium(Qs), iridium (Ir), lithium (Li) and aluminum (Al); and x is from 0.001to 0.999, wherein combining the amount of W with the amount of B and Mto generate the composite matrix comprises i) mixing W, B, and M togenerate a mixture, ii) transferring the mixture to a reaction vessel,and iii) heating the mixture to a temperature sufficient to induce areaction between W, B, and M to generate the composite matrix, andwherein the mixture is heated from about 5 minutes to about 540 minutes.2. The method of claim 1, wherein at least 10% of the atmospheric oxygenis removed from the reaction vessel.
 3. The method of claim 1, whereinthe mixture is heated to a temperature between about 1200° C. and about2200° C.
 4. The method of claim 1, wherein the mixture is heated by aninduction furnace or conventional furnace.
 5. The method of claim 1,wherein M is at least one element selected from the group: vanadium (V),chromium (Cr), niobium (Nb), molybdenum (Mo), tantalum (Ta), and rhenium(Re).
 6. The method of claim 1, wherein the ratio of B to W and M isless than 10 equivalents of B to 1 equivalent of W and M.
 7. The methodof claim 1, wherein the reaction vessel and mixture is separated by ametal liner.
 8. The method of claim 1, wherein the composite matrix is acrystalline solid characterized by at least one X-ray diffractionpattern reflection at a 2 theta of about 24.2.
 9. The method of claim 8,wherein the crystalline solid is further characterized by at least oneX-ray diffraction pattern reflection at a 2 theta of about 34.5 or about45.1.
 10. A tool comprising a composite matrix produced by the method ofclaim
 1. 11. The method of claim 1, wherein the mixture is heated forabout 180 minutes to about 540 minutes.
 12. The method of claim 1,wherein the mixture is heated by hot pressing.
 13. The method of claim1, wherein the mixture is heated by plasma spark sintering.
 14. Themethod of claim 1, wherein the mixture is heated by electric arcfurnace.
 15. The method of claim 1, wherein reaction vessel is coatedwith electrically insulating material.
 16. The method of claim 15,wherein the electrically insulating material is hexagonal boron nitride.17. The method of claim 5, wherein x is from 0.001 to 0.200.
 18. Themethod of claim 5, wherein x is from 0.201 to 0.400.
 19. The method ofclaim 1, wherein the density of the composite matrix is 4.0-9.0 g/cm³.